Car Rough Idle and Tach goes to Zero and shuts off. It will restart and drive at normal speeds but shut down at Idle.

[Buzzard67]

It's Bill from Duluth, MN. My job has finally brought me back home and I took the Buick out of storage.

It has some problems that I hope we can get together and discuss soon.

But at the moment it's at Local Garage 

I drove it to Hayward, WI a couple of weeks ago and ran some new gas through it. No problem. Then It sat for a week and went to drive it around town and when I started it the idle revved high then I pumped the gas pedal a few times and it resolved.

Now I drive it roughly 10 miles and it dies at the stop light. Restarts fine drives about  .25 miles dies, restarts- drives about .25 miles and checks engine light turns on. I park it at the Petco parking lot and try starting it again but it is acting like it's starving for gas. I pump the pedal ( like in the old carburetor days ) it starts but will only stay running if I feather the pedal.

I called the tow truck and had it towed to Local Garage.

They informed me the reason it was doing this was the head gasket. Check the engine light for the head gasket. Never heard of it. Now it's still at the shop and it didn’t change the original symptoms.

They want to start guessing at what it could be and have me throw money at it until they figure it out. I’m not good with that solution.

If you have any knowledge about these issues please forward them to me so I can pass them on to the garage, before I have to take out a 2^nd mortgage.

Thanking you,

 

Stopped by the garage today and I talked with the guy at the desk

And offered to share the information you had sent me as well as detailed instructions on the self-diagnosis dashboard codes and how to access them. He seemed uninterested but took the information. I asked what codes it was showing and he said something to the effect of “ cam sensor or cam adjusters “ he said it keeps turning on and off. He thinks there is a short or bare wire making contact and grounding out. I’m losing faith in this approach. It ran flawlessly once you got it passed idle on the open road. I believe I already paid for a head gasket it didn’t need. I’m no mechanic but I’m smart enough to listen to good advice. 

Once again any help or advice? Do any of these symptoms sound familiar?

 

Thanking you,

[Ronnie]

Ask your mechanic what the fuel pressure is at the fuel rail. He should already have tested the fuel pressure at this point and know the answer to that question. If he can't answer that question you should find another mechanic.

[2seater]

Well, the first thing to do is check the fuel pressure if you have an inkling that it is starving for fuel. You said it was stored for a time. How long and was it prepared in any way to be stored? You have Jim Finn right in your backyard, an excellent vendor for parts.

[2seater]

Same page, eh Ronnie🙂

 

Is this the headgasket story from Facebook? Pretty rare for a headgasket failure on a 3800 unless it was severely overheated and even then the short and stiff iron heads are pretty tough. Have you tried reading codes and using diagnostics yourself? You can't hurt it by experimenting while learning how to do it and the shop doesn't sound well versed in 30+ year old technology.

[2seater]

I forgot the title about losing tach and rough running while sounds like the ICM. Maybe two issues. Spark testers will tell the tale if spark quits.

[TripleC321]

IAC? If it stalls and stops at idle, then my guess would be the IAC. 

[DAVES89]

Do the simple things one at a time. Clean the Idle Air Control and the housing it fits into. Check the Mass Air Flow Sensor. Could be the Coil Pack/Ignition Control Module.

 This is why I have extra tested ones in the parts bin. I can swap them out [MAF Sensor and Ignition Module/Coil Pack] and then know what the problem isn't. Check the fuel pressure as Ronnie and 2seater think [You can rent a fuel pressure sensor for free from the chain parts houses]

[Buzzard67]

Thanking everyone for the great advice.

Stopped by the garage again today and tried having an exchange of ideas. But I got the feeling that their $50,000 dollar diagnostic machine knew much more than a person with a piece of paper. I tried to educate them on the try and true knowledge, ownership, and dedication of the Buick Reatta forums. 

I got the impression that if they kept replacing parts with no clear evidence of an actual direction eventually they will solve the mystery. At my expense of course .

I have been in touch by email with Jim Finn who has been a great source of knowledge. His emails have mirrored the above advice. 

The garage reiterated how bad the head gasket was, you could have hit a baseball through it. Yeah right. It ran just fine on the open road and had plenty of power ( what little they have ). 

I own or have owned many Subarus and I know what a blown head gasket acts like and performs. I never had a check engine light turn on for a head gasket.

The only thing they seemed receptive to was the fuel pressure ideal. But everything else fell on deaf ears.

All hail the million-dollar diagnostic machine.

Keep you updated,

Thanking you

Bill

[Ronnie]

Here are two things the $50k diagnostic machine apparently doesn't know.

 

1. There are no codes for a blown head gasket.

2. The camshaft position sensor won't cause the engine to die, even if a code is set.

 

I wonder if they call it a $50k machine because that is what they paid for it or because that is what they have made off their customers from using it?

[2seater]

If they are using modern equipment for OBD2 to diagnose a 1990 Reatta, they won't get a result. Maybe they are looking at exhaust gases in the coolant? It seems we have statements made but the evidence of how the conclusion was arrived at is missing? It seems the shop is blaming a mechanical failure when the evidence suggests a sensor or control malfunction. I don't understand how a headgasket could be diagnosed without documentation? Leak down test, compression test, exhaust in the coolant or coolant overflow from being pressurized by cylinder compression, coolant in the oil. What's the evidence?

[Buzzard67]

Any thoughts on a good scanning tool I can keep for my car?

[2seater]

32 minutes ago, Buzzard67 said:

Any thoughts on a good scanning tool I can keep for my car?

Is there something wrong with the onboard diagnostic system? There have been a couple of recent threads where the owner has found a scanner that works, a Tech4 or something like that, which seems to work well but at the same time, I didn't see any data that wasn't available from the built in system. I am not knocking the scanners as it may be more comfortable to use or the onboard system is suspect.

[Ohjai]

I purchased the Vetronix Tech 1A that the GM shops used.  You need the scanner, modules, cables and adapters.  It works fine for me, but I like gadgets.