Another CIS question

[T77911S]

Originally Posted by MotoSook

Good grief! I just spent 10 minutes typing a reply and hit the wrong button and loss it all.

sk.

oh i HATE that. there is a "back" button on my phone right below the M. the keypad is small enough as it is so i hit that sucker a lot. makes me want to smash the phone.

[Parr]

I'm really striking out in the Lansing, MI area on finding someone with knowledge of this system with the appropriate equipment to set it up. Looks like I'm going to have to take my car to Munk's in Waterford, MI. Thanks for your help.

[timmy2]

Your statement about worse performance when wet makes me think about some threads on the O2 connector failing in the engine bay.
How did the connector look when you replaced the sensor?

[1982911SCTarga]

As others have pointed out, all you need is a gauge set, a duty cycle/dwell meter and simple tools. CIS basic or CIS K-Jet is pretty easy to understand once you educate yourself about it.

Actually, I think us DIY'ers do a better job of setting up our CIS cars than a shop can because we can adjust and tune for virtually any ambient condition we experience (winter, spring, summer, fall). Heck, Don can tune his car from the driver's seat.

Brian

[1982911SCTarga]

Worse performance when wet can also be bad/failing plug wires.

Brian

[Parr]

The plug wires are like new and the plugs were changed 10,000 miles ago, so I don't think it's the plugs. The 02 sensor seems to be working properly because the hunting went away as soon as it was changed, and once warm, my idle is 900 on the dot.

When it's wet out, the idle will go way down to to 650, especially after getting off the freeway. I'm guessing it's a rich condition based on reasoning that the little air flow to fuel I am getting is even less when there is thicker/moist air.

I think what I want to do is have someone set up my CIS once, and hopefully they will let me watch them do it. Then, I'll pick up the appropriate tools and adjust it myself going forward. At this point, I'm not comfortable doing anything other than testing the WUR by myself, and I think there is great value to getting my car on an analyizer.

[Parr]

I checked my WUR this morning. The # on it is 072 and I hooked up my multimeter, and I was only getting 12-13 resistance. The car was not warmed up. Should I warm it up to get a more accurate reading? Is my WUR the problem?

[tirwin]

Parr,

First, don't sell yourself short. This is not rocket science, although it sure can feel that way at times.

Secondly, let me share my personal experience. I took my car to a shop partly out of frustration, and they "fixed" my issue by unplugging the pressure plate sensor. That is very disingenuous and not a fix at all. So, if you are going to go that route, make dang sure you take it to a reputable place.

The idle dropping that low when it's wet makes no sense to me. Something else is going on. Do you have the OEM style braided plug wires with the ground strap?

You have not yet checked your fuel pressures, right? It is not that hard. If I can do it, so can you. You need a set of CIS fuel pressure gauges and a $10 worth of parts from any auto parts store.

Originally Posted by Parr

The plug wires are like new and the plugs were changed 10,000 miles ago, so I don't think it's the plugs. The 02 sensor seems to be working properly because the hunting went away as soon as it was changed, and once warm, my idle is 900 on the dot.

When it's wet out, the idle will go way down to to 650, especially after getting off the freeway. I'm guessing it's a rich condition based on reasoning that the little air flow to fuel I am getting is even less when there is thicker/moist air.

I think what I want to do is have someone set up my CIS once, and hopefully they will let me watch them do it. Then, I'll pick up the appropriate tools and adjust it myself going forward. At this point, I'm not comfortable doing anything other than testing the WUR by myself, and I think there is great value to getting my car on an analyizer.

[tirwin]

Originally Posted by Parr

I checked my WUR this morning. The # on it is 072 and I hooked up my multimeter, and I was only getting 12-13 resistance. The car was not warmed up. Should I warm it up to get a more accurate reading? Is my WUR the problem?

I'll have to look up the -072 but if that resistance is too low, then it means the WUR will lean out the mix too quickly on a cold start. You do not need to warm up the WUR to take a better reading.

You're only testing part of the WUR with the resistance check. You need to know the system pressure, cold control pressure, warm control pressure and residual pressure. This requires the gauges.

Does your oil temp gauge have numbers on it or just the hash marks?

[Vereeken]

From reading the original post the behaviour of the car seems normal when cold.

The Ohm reading of the WUR is low, the 'fastest' WURs have an Ohm reading of about 18-22.
Tony has got all the testing data (i think he goes by the name of BOYTSC)
My car (a non 02 EURO car has got an Ohm reading of 32 and that is within spec for a 089).


The lower the Ohm the faster the bimetall warms the faster the fuel pressure increases the faster it leans out to normal.

You need to get pressure readings of the WUR before you go further.
You will also need to check the air sensor plate position and the timing at Idle and at 4.000 rpm.

I have struggled a long time with my car and the FP are essential. I have now made a last change to the position of the air sensor plate and that seems to have completed my very long trooubleshooting as it seems to have erradicated the last little glitch.

[boyt911sc]

Originally Posted by 1982911SCTarga

As others have pointed out, all you need is a gauge set, a duty cycle/dwell meter and simple tools. CIS basic or CIS K-Jet is pretty easy to understand once you educate yourself about it.

Actually, I think us DIY'ers do a better job of setting up our CIS cars than a shop can because we can adjust and tune for virtually any ambient condition we experience (winter, spring, summer, fall). Heck, Don can tune his car from the driver's seat.

Brian

Brian,

If you are adjusting and tuning your CIS every season of the year, then you are not setting the parameters correctly. A well maintained CIS engine would start any time of the year regardless of weather. If you have to tweak it seasonally, there is something inherently wrong with your system. Sorry to disagree with your post.

Tony

[Parr]

tirwin,

Yes, I have the braided plug wires.

[Jerome74911S]

Alright, I'm dumb on this point: Everybody says to be sure to check your CIS fuel pressures. OK, then what? How does this offer diagnostic help? Not trying to hijack, but I'm just ignorant and interested.

[boyt911sc]

Originally Posted by Jerome74911S

Alright, I'm dumb on this point: Everybody says to be sure to check your CIS fuel pressures. OK, then what? How does this offer diagnostic help? Not trying to hijack, but I'm just ignorant and interested.

Jerome,

All fuel injection systems depend heavily on the fuel pressure parameters. If the FP is running and delivering the incorrrect amount of fuel pressure this would be a major problem. Even if the FP is running perfect, if the system pressure is off by a lot from spec, this would be a problem. Even if the FD is good and delivering the correct system fuel pressure, and the control fuel pressure is off by a lot, this could be another problem. Even if the WUR is good and working, and the residual pressure is deteriorating very fast, this would be a problem. And I could add more to these.

So without knowing your fuel pressures (system, control, and residual) from start of your troubleshooting process, you are assuming all these conditions to be on spec. Sometimes you are lucky and they are in spec. But you can not rely on luck all the time for your diagnostic tests.

That is why a fuel pressure gauge kit is MANDATORY for fuel injection troubleshooting regardless what system (FI) you have. Others would chime in about this subject.

Tony

[47silver]

If the pressures are wrong then you can determine if is a problem with the wur or the fuel pumping system. If these check out then you test fuel injectors. If these check out then you can begin to isolate the air side.
You cannot guess, you systematically check each component. If you spend 400 bucks on tools, you will have the tools, and eventually have a car that runs like or in my case better than new.

[Parr]

UPDATE.

I had Munk's of Waterford, MI take a look at my car. They checked control pressures, timing and the fuel mixture. They found the fuel misture was too lean. This is after I richened the mixture slightly after changing the O2 sensor.

So, long story short, the problem was a bad o2 sensor. At some point, someone had compensated for the bad o2 sensor. The bad sensor was causing the frequency valve to dump too much fuel. Once the o2 sensor was replaced, the mixture was way too lean. Now that it is set, I'm not having further issues.