[semperfimama]

I've got a 94 eldorado with the 4.6, and i've got code p032 map sensor circuit open no other codes. After running a few minuites the exhaust manifold near the firewwall glows red. The map sensor has allready been replaced and i've erased codes several times and this is the only one that sticks around. Is it possable the CAT is plugged up and is causing the glow as well as throwing off the vacum level and triggering the MAP sensor fault. I checked the new andold map sensor with a vacum gauge and i think their good. any ideas?

I've also changed the ISC motor and it needs to be adjusted so it throws a code p030 ISC RPM out of range sometimes but i don't think thats part of the current problem.

 

[Ranger]

Check your FPR. It probably has a leaky diaphragm.

 

[semperfimama]

When it first broke down it stalled around the corner from a Cadillac certified shop, about 50 miles from home so my mom put it in there. They replaced the TPS, the FPR, and the MAP sensor. The part they call a FPR looks very similar to the MAP sensor to me. Im used to fords, where the FPR looks like a tuna can, was that actually the FPR they replaced? I need all the help i can get, im good at troubleshooting OBDI systems but there is some big differences between Cadillacs and Fords.

 

[Ranger]

The FPR is a small round canister with a nipple on it. It's mounted on the fuel rail and has a vacuum line attached to the nipple. In your case ('93 & '94) it is mounted inside the manifold, thus it is subjected to manifold vacuum so there is no need for a vacuum hose.

 

[semperfimama]

So how do i get access to it? What was the thing the shop replaced, some kind of sensor that monitors the FPR? Would a leaky FPR cause a P032? I tested the MAP sensor according to the Chiltons manual using my fluke voltmeter and I get 3.4v between pins A&B with key on. Both sensors read the exact same which makes me question if their really the problem. I'm in Dallas, TX which has an elevation of about 186m above sea level so according to Chilton's I should see a voltage range of 3.8 - 5.5 volts. I also checked the +5v refrence voltage on pin C and its good.

 

[Ranger]

You access it by removing the top manifold cover. Check it by turning the ignition on to energize the fuel pump, but DO NOT crank the engine. It will run away unthrottled and wide open. If any fuel leak from the nipple it needs to be replaced. The FPR is not monitored. I don't think that would cause that code.

 

[semperfimama]

What about the MAP sensor? should I replace it again? Is the quality of parts that low?

 

[Ranger]

I don't know. It's gonna be your call. You say it checks out good, yet you have a code saying it is bad.

 

[semperfimama]

OK, I got it figured out. I had several small vacum leaks that toghether were throwing off the MAP sensor so no more P032. Also had to perform the TPS/ISC learn proceedure. Someone messed with the minimum idle speed set screw and tried to compensate with the screw on the ISC motor. She idles beautifully now and is code free.

2 questions

1. The small vacum "tree" on the top of the TB is held toghether with nothing but HI-Temp silicon is it true that you can't get a replacement one (other than the junkyard) anymore?

2. When I turn off the motor the ISC retracts itself in and out for about 15 seconds and then stops is that normal? I don't have any codes showing (yet) but I just replaced it and I don't want to wear it out. I think it also does it for about 5 seconds if you turn the key to RUN but don't start the motor.

 

[semperfimama]

Nevermind about the clicking ISC, I performed the "learning routine" again and it stopped so I guess im good.

 

[semperfimama]

Well im back where I started. Took her out for about 30 miles of errands and she ran great at first. After my first stop the stupid ISC motors started going back and forth when i turn the key off and sometimes when its in RUN (it stops once the engine starts though). After my second stop I start it up and it dies. Code P032 and P071. It's not overheating but these problems seem to occur once the motor warms up. What in the world is wrong with this thing? I may need to put a shorter screw in the plunger of the ISC motor, because i have it all the way down and it still contacts the throttle slightly. Going down the road the thing surges and sputters bad, and dies occasionally.

 

[Ranger]

I'm not sure you can change the plunger bolt, but don't. It won't help. If it is ratcheting, it is bad and needs to be replaced.

 

[semperfimama]

Well ive got the isc completly out of the way and no matter what i do it keeps on ratcheting. The old one does it too. The car won't start even with the thing out and unplugged now. I went ahead and checked my fuel pressure at the shraeder valve by the cruise control and i get 40psi, which i believe to be good. Is there anything other than a bad ISC that can cause it to ratchet out of control? The thing should be able to idle on its own even without the thing. Why couldn't they just have used an Idle Air Control Valve like even my 93 bronco has?

 

[Ranger]

The thing should be able to idle on its own even without the thing.

No, with the ISC removed the throttle plate is closed and the engine gets no air at all. Try starting it with your foot holding the throttle cracked open. It should start then.

 

[semperfimama]

The proceedure for setting the minimum idle screw on the TB says to move the thing completly out of the ways and unplug it so that it has no effect on engine RPM. Then your supposed to an idle of about 450rpm no?

 

[semperfimama]

I can't get it to start that way either, thats why i went ahead and checked the fuel pressure too.

 

[Ranger]

The proceedure for setting the minimum idle screw on the TB says to move the thing completly out of the ways and unplug it so that it has no effect on engine RPM. Then your supposed to an idle of about 450rpm no?

Yeah, now that you mention it I believe that is correct. I was thinking IAC valve.

Have you checked to be sure you have ignition?

 

[semperfimama]

No, thats what i was thinking though. Got air and fuel. Whats the best way to do it ? Check resistance across each coil pack?

 

[Ranger]

I'd get an old spark plug. Pull one wire and plug the old plug into it and ground the base somewhere (don't hold onto it). have someone crank the engine and watch for a spark to jump the electrodes. If you don't have an old plug, pull one of yours and use it.

 

[semperfimama]

Well ive got spark to all plugs. Im running out of ideas. It turns over starts for a moment but then immediatly dies. If it would run at all id probably still get a p032. Can't get it to start with either MAP sensor installed though. I've got the ISC unplugged and completly removed from the vehicle at the moment.