Low Idle

onegreenev · 08-14-2013, 09:03 AM

Newly acquired 73 914 1.7 and I had to replace the distributor vacuum line to get it to start. The fuel is old but still starts pretty well. Idle came up a bit after driving it a little but now the idle is low when the car warms up and coming off idle its sluggish but once off idle it runs great. Not sure if its other vacuum lines or not but I do plan on changing all the rubber I can in the engine compartment. It is still fuel injection.

Ideas? If you need more information let me know.

Pete

onegreenev · 08-15-2013, 08:27 PM

Interesting no one had any thing to say about this. I found that the elbow for auxiliary air regulator was cracked beyond repair. I used a thick hose to replace that piece but it had to have a vacuum line installed. I took a small pick and punched a tiny hole in the middle of the hose and used my pliers to force into the hole a small metal tube that connects the vacuum line. Worked great. I have one more vacuum hose to replace but my idle is no longer at near zero but still too high at about 2100 rpm. The Aux Air Regulator still looks to be working. I will see if it is open in the morning when its cold. The wire is in good condition so I am not worried about that. How do you test the heater element? The car runs fine above idle.

Any ideas on how to lower the idle? Maybe that one other lower vacuum line on the distributor. I thought there was only one but found another that is routed low. I think I have enough vacuum line to replace that hose. If not I wlll use an old break line as a hard metal line and just use small rubber ends to finish out the line.

Pete

Any ideas would be great.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

If your idle is at 2100 RPM, you have a good-sized vacuum leak somewhere. Find it and plug it.

--DD

onegreenev · 08-16-2013, 05:18 PM

Now I am back down to near zero after fixing the hose that came off causing a vacuum leak. Sucks chasing this thing. Took nearly a 1/4 tank of fuel to drive 45 miles. Ouch. Had to heal toe the sucker to keep it running at a stop. Going to look at the AAR again after it cools down a bit.

onegreenev · 08-16-2013, 07:12 PM

Well, I removed my AAR again to check how well it would work. I found that the spade connector did not conduct any current so was not heating up and turning off. I checked the connection at the wire just before the spade connector and it conducted voltage. So I clipped off the spade and stripped the wire a bit and connected it directly to the battery to see if it would work. Damn that sucker gets hot. And yes it worked perfectly. The shaft turned enough to completely close off the vacuum. Now to connect it back up and see how well it works. So it was not working at all. Even after a drive home using heel toe to keep it running at stops and driving 22 miles it never closed off completely. Now it does. Letting it cool down a bit to see if will work after screwing it down again. Ill update later.

onegreenev · 08-16-2013, 09:13 PM

Well I got the wire shrink wrapped and a new spade with shrink wrap and got it all connected and bolted down with all the connections back where they belong and now it flat out won't start. Just cranks and cranks and cranks. Wife said it smelled rich.

Ideas?

Dave at Pelican Parts · Dave at Pelican Parts's Garage

You're using a lot of fuel, the car doesn't like to idle, and it smells rich.

Sounds like you're running rich...

How's the fuel pressure? Is the Manifold Pressure Sensor plugged into the manifold? Does it hold a vacuum?

--DD

onegreenev · 08-17-2013, 04:02 PM

No clue on the fuel pressure. Its pumping fuel for sure. Manifold pressure sensor? I have not received my book yet so I don't know what that looks like or where it plugs in? I have replaced a pile of old stiff rubber lines with new. Trying to not have to dig too deep.

Do you have a picture of the MP Sensor ? I see a bunch of stuff and it took a bit of digging to figure out what was what. Still learning on this one. I am more of an old VW carbureted car junkie. First Porsche Ive owned. So far not terrible in the fix it department. Loads to learn. Like low brake pressure will cause a blinking light on my dash and can be reset on the pressure sensor on the brake light switch on the master cylinder. Thought I had a doozie of an electrical problem.

Pete

I will be going out to have a look.

I am all ears on what may be the issue. Photos would help too. Thanks a whole bunch.

Pete

onegreenev · 08-17-2013, 05:08 PM

Checked the engine compartment and nothing looks out of place nor is anything disconnected. Unless there is some super hidden item I am not seeing, I can't say anything is disconnected. I also was unable to find the flashing brake light reset button on the brake switch on the master cylinder. I climbed up under the car and removed the spades and had a hard look and feel and there is NO reset switch. How do you disable that annoying flashing light.

onegreenev · 08-17-2013, 08:25 PM

Been going over all the articles I can find and checked out the Manifold Pressure Sensor and found it to hold a vacuum just fine with no leak down. All the hoses check out and I need to put a couple hose clamps on a couple hoses just to be sure there is no vacuum leaks. It was running and now it just cranks and stinks of gas. Could it be as simple as fouled plugs at this point? Could not get it started after doing a bunch of hose replacements so I don't know if what I have done is working or not.

Not sure why there is not much reaction to this posting but I assure you I am doing what I can. I am hoping for my manual to show up in a few days. Not sure how much that will help but I have very little experience on FI systems of the early VW.

Pete

I need help. I want to drive, not tinker.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The plugs are likely fouled at this point, yes. But there is probably more to it than that.

Sounds like you found the MPS, and checked it. That's good.

There is a sensor in the cylinder head near the #3 spark plug, the Cylinder Head Temp sensor (CHT, Temp Sensor II, etc.). If that is unplugged, the mixture will go so rich the car usually does not run. Look for the wire coming out of the engine tin near the #3 plug; it should go into a plastic plug nearby. Check to see if that's plugged in securely.

Have you read through Brad Anders' D-jet guide? It contains just about everything that is currently known about D-jet EFI these days. Brad's '70 914 2.0L

--DD

onegreenev · 08-18-2013, 06:37 PM

Head sensor is plugged in. Checked the plugs and they were not terrible but changed them anyway for now. The old ones still look quite new so they will clean up nice and still be usable. Oh yea! the CHT sensor is plugged in solid. Did not check that resistor but gotta find it first. I did however get it to chug a lug a little but could not get it going. Arrrrrrg

onegreenev · 08-18-2013, 08:57 PM

After reading some of the articles presented to me to read it seems like the D-Jet EFI is just a pain in the butt. Sounds like I should just ditch the D-Jet and put in Dual Carbs. What would one need to do that successfully? If not I will just go with our original plan but a bit earlier than planned and just rip out the engine and said components and just do our electric drive conversion now instead of next year.

Pete

I actually wanted to just drive this for now. But I can move forward with the electric conversion. It will have more power than a stock 2.0 so maybe it will be the best. No damage to the car will happen with the conversion.

onegreenev · 08-20-2013, 06:12 AM

Where do you find the resistor that is between the cht and computer? I did not see its location. Is is located in the plastic covering for all the wires going to the computer? If so then I must ruin a nice looking harness. Arrrg.

Pete

Dave at Pelican Parts · Dave at Pelican Parts's Garage

If a resistor is present, it will look like a longish oval "pill" in between two plastic box connectors. It will be over by the #3 spark plug, with one of the connectors plugged into the CHT sender wire, and the other box plugged into the FI wiring harness. The whole resistor-wire-connectors deal is maybe 6" long. It is not inside the wiring harness tubing.

The one box connector is the regular one that is on the FI harness, the other is actually on the resistor.

Here is a pic from an earlier post:

--DD

onegreenev · 08-20-2013, 04:45 PM

Thanks, I'll do some more hunting for that piece.

onegreenev · 08-21-2013, 06:53 PM

No such resistor in my system. I did however get it running but still quite low idle. All components check out. While idling I was able to check the wires and at first number 1 and 2 cylinder made no change in idle. Checked out the wires. No difference or change but I did finally get number 1 and 2 to make a slight change in idle when pulled off. I noticed that when I pushed on the vacuum canister on the distributor the idle went up a bit. I am thinking maybe that the prior owner had mucked with the distributor a bit in his attempt to get the car running. So I will to a tad movement on the distributor.

Pete

Still no manual yet. Slow mail.

seventythree · 08-22-2013, 06:40 AM

The reason you're not getting much help on this thread is because troubleshooting this kind of a drive-ability problem on a 914 is a real pain in the a$$.

In any case:
1) If pushing on the vacuum canister is affecting the idle, you may have a timing issue. Remove the distributor and fix the loose vacuum canister. Then install and re-time.

2) Fix the problem with the injectors not firing first or any time spent on setting the timing will be a waste. If #1 & 4 or #2 & 3 pairs weren't firing correctly, that would indicate a problem with the FI trigger points, which is also inside the aforementioned distributor. However, if #1 & 2 or #3 & 4 pairs are misfiring, or not firing at all, the problem is with their respective grounding. There is a grounding point near the throttle-body, under the intake runners on the passenger side. Two spade type connector push onto it which provide grounding to the injectors in the order mentioned above. In my case, the #3 & 4 connector had slipped off and was making intermittent contact. This connection area will be difficult to reach and service unless you remove the passenger side intake runner.

I hope this helps.

onegreenev · 08-22-2013, 07:30 AM

Not really but it is more to look into. The canister on the distributor is actually not loose. But if you do push enough it moves just enough to notice a difference. It will still start and all cylinders are firing. I moved the distributor and the idle comes way up to 2000 rpm. Not terrible smooth either. Once and awhile it seemed to misfire.

So the one thing for me to look at would be the grounding points. I guess I need to remove the intake runners and replace the gaskets while I am at it and to replace the center rubber pieces. I will have a deeper look.

I am not going to go too deep as it usually ends up costing way too much and since our end goal is an electric car anyway. I wanted to have it running good so I could sell the engine as a turn key. If it is not running good I can't recoupe much because it is not running good.

But I will look deeper.

I am very aware of diagnosing over the internet and I am very aware that it is a total pain in the ass but it is worth doing. I do it all the time for others for their VW's. It is also a pain that more folks are not doing this and choose to allow the person to mostly flop around like a fish out of water.

I do thank you for your input. I will look.

Pete