Well... dang. CIS problem back.

[tirwin]

I'm a bit grumpy right now. Need you guys to tell me if I should be grumpy or not.

Many months ago (back before I started my interior restoration project), I was working through some CIS issues. Got lots of great help and feedback here. In an effort to rule out vacuum leaks, I took the car to a local shop to get a smoke test done. And I had some other unrelated things done at the same time. Of course the conversation progressed to what my problem was (cold start) and they felt certain they could fix it.

Got the car back and it was "fixed". They said they adjusted the idle and mixture. I travel a lot for work so I got the car home and then had to go out of town. I was happy. When I got back in town and got back behind the wheel, I noticed that the fuel pump was running with the ignition on, which is not normal.

I posted on here about it, and John Walker responded that the sensor plate connection on the back side of engine was probably disconnected. It was. I couldn't feel where the wire should plug back into so I left it disconnected for a while. Not a problem because the car has been sidelined while I was redo-ing the interior.

So last night someone posted a different thread asking about the same plug. It has a green connector on it. Aha! That's the same plug as mine! Then someone posted a nice picture. This morning I went out to the garage armed with better info on where the connection goes and I found it and plugged it back it. Turned the key to the on position. No fuel pump running. Bingo! I'm in business.

Then I started the car, and my old CIS cold start problem is back.

Before I get all wound up over this, is it even possible that the fact that the fuel pump running before the car is cranked would "solve" my cold start problem?

You see where I'm going with this, right? Did I pay someone to fix my problem by just unplugging the connector. That is not fixed. That is a band-aid.

I'm not going to post the name of the shop. I'm not trying to jump to conclusions. But from where I sit at this point, it is hard for me to draw any other conclusion.

Am I crazy?

[Porchcar guy]

Why not take it back and discuss the issue ? If they are reputable, they should take care of this.

[tirwin]

I probably will, but I'd like to be armed with better knowledge before I walk in and basically accuse someone of taking a shortcut. And in fairness, they will likely say it's been a long time, yada yada yada. If it is indeed plausible that the "fix" was to simply disconnect the sensor plate connector, then I'm not sure how much more help I could stand from those guys.

[RarlyL8]

I don't know what your original cold start problem was, but one cause can be masked by allowing the fuel pump to run in the on position. That cause is fuel pressure bleed down. If your fuel pressure check valve or fuel accumulator are malfunctioning the system pressure will bleed down in an irratic manner causing difficulty cold starting and eventually hot starting. In the early stages of failure if the pump fires in the on position the pressure will jump up before the starter engages and the engine will fire quickly.
I'm not saying this is what you are experiencing, only what is possible.

[T77911S]

it is possible that it is helping with the cold start. a easy test would be to unplug it again and test it.

if it is helping with cold starting, you are likely loosing pressure while it sits. this would also show up with hard starting when hot after about 45 minutes of being turned off.

residual pressure needs to be checked. you might as well get cold control pressures (CCP), warm control pressures (WCP) and system pressuresm checked. write these down for future reference, and or post here.

[Joe Bob]

CIS is ALL about proper fuel pressure, for start up, running, cold or hot start and has different issues for different problems.

I would get a Bentley manual for education.....but cold starts involve the fuel pump, WUR, the CHT and fuel distributor. All or one can be an issue. The fuel that was in the in the tank could have gunked up one of them.

The making the pump run brought your pressure up so that it starts. Don't let it run long as it can hydrolock the cylinders.

Could be as simple as some Techron thu the system or a need to throw a gauge on it to see where you are losing pressure.

How are hot starts?

[tirwin]

Originally Posted by RarlyL8

I don't know what your original cold start problem was, but one cause can be masked by allowing the fuel pump to run in the on position. That cause is fuel pressure bleed down. If your fuel pressure check valve or fuel accumulator are malfunctioning the system pressure will bleed down in an irratic manner causing difficulty cold starting and eventually hot starting. In the early stages of failure if the pump fires in the on position the pressure will jump up before the starter engages and the engine will fire quickly.
I'm not saying this is what you are experiencing, only what is possible.

Brian,

Thanks for the response. I have yet to look at those things and what you're saying makes sense based on other CIS threads I've read.

I think I'm going to go back and start at the beginning of troubleshooting this problem -- maybe start a new thread.

I always like to give people the benefit of the doubt but I think I'm done with that shop. Makes me wonder if they even ran the dang smoke test.

[tirwin]

Originally Posted by T77911S

it is possible that it is helping with the cold start. a easy test would be to unplug it again and test it.

if it is helping with cold starting, you are likely loosing pressure while it sits. this would also show up with hard starting when hot after about 45 minutes of being turned off.

residual pressure needs to be checked. you might as well get cold control pressures (CCP), warm control pressures (WCP) and system pressuresm checked. write these down for future reference, and or post here.

Exactly. Later this evening I'll pull the plug again and test it out. If the cold start problem goes away then I'll have my answer.

Last time I did all the ccp, wcp, rp tests residual pressure was ok.

Probably need to start from scratch.

[tirwin]

Originally Posted by Joe Bob

CIS is ALL about proper fuel pressure, for start up, running, cold or hot start and has different issues for different problems.

I would get a Bentley manual for education.....but cold starts involve the fuel pump, WUR, the CHT and fuel distributor. All or one can be an issue. The fuel that was in the in the tank could have gunked up one of them.

The making the pump run brought your pressure up so that it starts. Don't let it run long as it can hydrolock the cylinders.

Could be as simple as some Techron thu the system or a need to throw a gauge on it to see where you are losing pressure.

How are hot starts?

I have only ever had one hot start issue that I recall. It cranked, choked out, and then fired up on the 2nd crank.

Good point about the hydrolock.

I bought a few cans of BG44k a while back. Maybe it just needs to be burped.

I'm gonna start the CIS troubleshooting from scratch since it's been awhile now and the car's been sitting a lot while I've been doing all this interior work. There is an old thread on here that has my "notes" I'll have to dig up.

I'll have the driver's seat back in soon. Got a couple of other things to button up before I can get back on the road (I've only said that 487 times but who's counting?). I am so dang slow on getting the interior done because I have to work in fits and starts. As a coach once said, "I wouldn't exactly say he's slow but you could time him with a sundial."

[boyt911sc]

Originally Posted by tirwin

I have only ever had one hot start issue that I recall. It cranked, choked out, and then fired up on the 2nd crank.

Good point about the hydrolock.

I bought a few cans of BG44k a while back. Maybe it just needs to be burped.

I'm gonna start the CIS troubleshooting from scratch since it's been awhile now and the car's been sitting a lot while I've been doing all this interior work. There is an old thread on here that has my "notes" I'll have to dig up.

I'll have the driver's seat back in soon. Got a couple of other things to button up before I can get back on the road (I've only said that 487 times but who's counting?). I am so dang slow on getting the interior done because I have to work in fits and starts. As a coach once said, "I wouldn't exactly say he's slow but you could time him with a sundial."

Tirwin,

Your problem could be simply caused by out of spec fuel pressures and/or unmetered air. These should be investigated first, before spending too much time and effort. The early CIS engines ('73.5-'75) have running FP's when you set the igintion switch @ ON position and they don't hydrolock!!!!! Unless you let the fuel injectors spray too prematurely long before start-up,it would flood the combustion chamber/s.

CIS is a very simple and easy system to maintain. The biggest problems we have are people doing DIY guess-work in their troubleshooting. I've been searching for a while for CIS problem/s that could not be diagnosed or fixed correctly by a DIYer like us. Nada!!!!

This forum alone has been very successful in solving these problems. These guys are good. Just provide the information and feedbacks, and every conceivable troubles would be diagnosed and corrected. That's why we all spent time here.

Tony

[tirwin]

Originally Posted by boyt911sc

Tirwin,

Your problem could be simply caused by out of spec fuel pressures and/or unmetered air. These should be investigated first, before spending too much time and effort. The early CIS engines ('73.5-'75) have running FP's when you set the igintion switch @ ON position and they don't hydrolock!!!!! Unless you let the fuel injectors spray too prematurely long before start-up,it would flood the combustion chamber/s.

CIS is a very simple and easy system to maintain. The biggest problems we have are people doing DIY guess-work in their troubleshooting. I've been searching for a while for CIS problem/s that could not be diagnosed or fixed correctly by a DIYer like us. Nada!!!!

This forum alone has been very successful in solving these problems. These guys are good. Just provide the information and feedbacks, and every conceivable troubles would be diagnosed and corrected. That's why we all spent time here.

Tony

Thanks, Tony.

You and ossiblue helped me out when I was first cutting my teeth on the CIS problems back when I bought the car and I certainly appreciate the help. I thought I had this problem licked.

One of the reasons I took the car to this shop was because of the advice on this forum -- as I newbie I was willing to pay someone to double-check me that unmetered air wasn't an issue. They said they did a smoke test, ran it for 30-45 minutes and didn't see a puff anywhere.

My problem is now that I paid someone to do a job and it sure seems like instead they covered up the problem. I can't say conclusively at this point, but again, after I went from great starts to chugga-chugga-wheeze this morning after plugging in the sensor plate connection... well I was more than a little irritated. Operating on the assumption for the moment that the wrench took the cheap way out and didn't really fix the problem, I'm not sure I can believe they did the smoke test. I didn't see it with my own eyes. So I'm back to square one.

I'll start another thread soon when I can focus on this problem and ask for your help and patience again. I'll run all the basic tests all over again starting from square one. Hey, at least I have practice. I know I can get this fixed.

[RarlyL8]

What is curious (to me) is that the shop would have to know that the fuel pressure is bleeding down too quick AND that you can mask it by allowing the pumps to run in the on position. If they knew all that then why not charge you to fix the problem?
No worries on hydro-lock unless you move the air meter plate and activate the injectors. This is how the fuel system pressures are checked. The (excess) fuel returns to the gas tank.

[tirwin]

Brian,

You are right. I don't understand it either. I could speculate but probably best not to. There were other things done at the time -- turn signal stalk replaced, alignment, lowered to Euro height, cleaned some old corrosion around the battery tray area and treated with POR-15. I think there were a couple of other things too.

All I can say for sure is what I saw today. Fuel pump didn't run like that before I took it in. It did after. The blame is squarely mine for not going back at the time and addressing it. Here is the thread I started (wow... it was almost a year ago! time flies...) when I thought the FP pump running was related to the electrical. As you can see, ossiblue and John Walker both nailed it -- and I didn't say anything about the smoke test or any other engine work yet they clearly knew where to look. I did rule out fuel pump relay because I had ordered a spare relay from Pelican at the time to keep in the glove box.

Something ain't right

Re-reading the thread it is interesting that I also asked a follow-up question that I don't remember asking -- "might be a crazy question at first but I have to ask. Would the fuel pump turning on a half second before the starter motor possibly improve a cold start problem?" I really don't remember asking that question or why I did. As you can see I didn't get an answer. Stupid me for not following up.

At this point, I doubt going back to the shop will do any good. I've got no real proof of anything and no good can come out of it. It's been many months -- they'll say anything could've happened in that time. If they did nothing wrong, all I've done is unjustly insult their integrity and they won't want me as a customer. If they did do something wrong, well... they're crooks. You have to trust your mechanic and it comes down to I don't think I can. Probably best to move on and chalk it up to a lesson learned the hard way.

This just has me more determined than ever to get it fixed. And I'm happy to rely on my fellow Pelicans.

[tirwin]

You know guys, you just have to laugh at yourself sometimes. I'm blessed to be an "expert" at what I do... whatever that means. It puts food on the table and a roof over the head of me and my family and lets me tinker with this old car that was on a poster in my room when I was a kid. Good thing I don't do this for a living... I'd be broke. But I'm learning a lot and (mostly) having fun.

[boyt911sc]

Originally Posted by tirwin

You know guys, you just have to laugh at yourself sometimes. I'm blessed to be an "expert" at what I do... whatever that means. It puts food on the table and a roof over the head of me and my family and lets me tinker with this old car that was on a poster in my room when I was a kid. Good thing I don't do this for a living... I'd be broke. But I'm learning a lot and (mostly) having fun.

Tirwin,

If you have the time and interest to do certain things in life, you'll find a way to do it. Some have the time but won't do it. Others have the desire and interest to do it but lacks time to do it. So this depends on individual's personality and attitude. Sometimes, it is better to pay someone to do it than do it yourself.

As far as CIS troubleshooting and keeping your engine running regardless of weather, any average DIY'er would have an easy time doing it. It does not require special skills and sophisticated tools to evaluate and fix the problems. Understanding the basic principles of K-Jetronic (CIS), listening to advises, and benefiting from the experiences of others would make you another success story.

Tony

[T77911S]

tony is right. for me now, if the price is right, i pay soemone to do it, like rebuilding my targa top. i started to do it, but figured the time to do it and reseacrh and aquire all the parts, it was better to pay someone.

with CIS, you can learn to fix it with help here. first thing is to get a set of gages and check the pressures i mentioned above.

brian, i thought the same thing. either they got lucky and unplugged the connector to make the FP run or they had some idea of what they were doing, but why not fix it right, unless they just wanted to charge a lot for a "quick and easy fix". time is money.

running the FP would help with cold starts, and i think porsche saw the need to have more pressure for cold starts, but they also thought it was safer to not have the FP running when the engine is not, whichis why they made changes to help with that.
they added a check valve inthe pressure regulator that blocks the return from the WUR back to the tank. it closes as soon as pressure drops below system pressure, which is above the WUR control pressure. so now the fuel line is trying to stay pressurized from the pressure regulator check vaLve back thru the WUR thru the FA and finally to the FP by the check valve there. it should also be higher than the older cars that did not have the check valve inthe pressure regulator.

[tirwin]

Originally Posted by T77911S

tony is right. for me now, if the price is right, i pay soemone to do it, like rebuilding my targa top. i started to do it, but figured the time to do it and reseacrh and aquire all the parts, it was better to pay someone.

with CIS, you can learn to fix it with help here. first thing is to get a set of gages and check the pressures i mentioned above.

brian, i thought the same thing. either they got lucky and unplugged the connector to make the FP run or they had some idea of what they were doing, but why not fix it right, unless they just wanted to charge a lot for a "quick and easy fix". time is money.

running the FP would help with cold starts, and i think porsche saw the need to have more pressure for cold starts, but they also thought it was safer to not have the FP running when the engine is not, whichis why they made changes to help with that.
they added a check valve inthe pressure regulator that blocks the return from the WUR back to the tank. it closes as soon as pressure drops below system pressure, which is above the WUR control pressure. so now the fuel line is trying to stay pressurized from the pressure regulator check vaLve back thru the WUR thru the FA and finally to the FP by the check valve there. it should also be higher than the older cars that did not have the check valve inthe pressure regulator.

My wife wishes I'd pay someone (reputable) too!

Back in the winter I kicked her car out of the garage so I could gut the old interior. I work on it when I can get time between work and family stuff. I can see light at the end of the tunnel.

Since I bought the car, I've done quite a lot to it. When I first got it, it would regularly backfire on cold start and it idled rough. I went through and did a bunch of maintenance -- oil change, new plugs, plug wires, cap rotor, etc. That made a huge improvement.

I have fuel gauges and was going through all the normal tests with help from the forum, but I just wasn't confident that I didn't have unmetered air somewhere so that's why I took it to the shop. At the time I was trying to get a few things sorted quickly so I could take it on a road trip down to the Hilton Head Concours show (not to be IN the show, just to go).

When I told the shop I wanted a smoke test, they of course wanted to know why and I explained the cold start issue. They thought it was a matter of adjusting idle and mixture based on what I had already done.

So like I said earlier I got the car back and thought that's what they did. I didn't notice the FP running when I picked it up. I was in a hurry to get out of town for a business trip. When I got back a week later is when I first noticed the FP running but given the door buzzer wasn't working either when I got it back, I thought it was an electrical problem. (Shop was in the dash to replace the turn signal stalk.) I know for a fact the FP issue didn't exist prior to me taking it to the shop because I had to jump the FP relay to do the cold control pressure test so I know the sound of the running FP.

Having plugged and unplugged the sensor plate connector a couple of times now, it absolutely didn't just come loose. That thing is as tight as Dick's hatband, as The Duke would say. Quick fix? Draw your own conclusions.

I have to finish up the interior so my wife can have her spot in the garage back or I'm gonna be sleeping in the car. And I've got some trips in the next couple of weeks so I'm probably not get back to this until then.

The bright spot in all this is at least now I know where to look to fix the problem.

I will get it fixed this time around. If you want something done right, you gotta do it yourself...

[T77911S]

good call on haveing the smoke test done. that eliminates a lot.

the idle and mixture should NEVER be adjusted without first fixing air leaks, checking fuel pressures and a basic tune up. that was the first flag that caught me eye with the shop.

if it was me, i would leave the FP running, fix the wifes car then go back and fix the 911. since you have gages, its just a matter of checking pressures.
sounds like you could have CCP issues (WUR) with the backfiring when cold and its probably just the FA or the check valve at the FP causing residual pressure loss, if you do have pressure loss. but that needs to be checked.
none of this is very hard to figure otu and you can do it.

the only hard thing after all this is setting the mixture, and you can just pay for that to be done after everything else is done.

[tirwin]

So here's my dillemma... If the shop just pulled the plug, how can I trust that they ran the smoke test?

I did not seem to have any problem with residual pressure before, but if the problem is with the check valve or FA, would I see a drop in residual pressure between the WUR and the FD? Or maybe it is very slow and I didn't wait long enough. What would a normal residual pressure be after sitting overnight?

And it's the 911 I gutted. I just moved the wife's car out for work space.

If I can do the headliner, I can fix this...

[boyt911sc]

Originally Posted by tirwin

So here's my dillemma... If the shop just pulled the plug, how can I trust that they ran the smoke test?

I did not seem to have any problem with residual pressure before, but if the problem is with the check valve or FA, would I see a drop in residual pressure between the WUR and the FD? Or maybe it is very slow and I didn't wait long enough. What would a normal residual pressure be after sitting overnight?

And it's the 911 I gutted. I just moved the wife's car out for work space.

If I can do the headliner, I can fix this...

tirwin,

Working on the headliner replacement needs patience and craftmanship. I wanted to do it on my '73 VW Beetle but kept postponing it. I guess I'm worried about failing to do a nice job with the headliner job. Yet, I went into engine rebuilding not too long ago and just completed my 10th engine rebuild. The 11th and 12th are all lined-up for the winter season.

So doing your CIS troubleshooting would not be difficult at all for you. It is the anxiety that you have to overcome. There is nothing to it!!!!! If you believe you like to do it and want to do it, you'll be able to do it. Help and assistance are here at the forum. What you need is practice. That's all!!!!

Find someone who knows and understand K-Jetronic. This is an antiquated FI technology and no longer used by car manufacturers the last 20 years. You might call this as an obsolete system.

Tony