Well gang I fell for the good old “ran good when parked” line and I’m at wits end.

The car is an 89 Formula with he 5.7 TPI. The engine was rebuilt (have paperwork) and it has very minor mods such as a mild cam, headers, exhaust and a Hawks RamAir hood.

Issues:

1. Hard starts
2. Fluctuating idle
3. At times it will idle high (2k rpm) and when it idles high, the peddle is very responsive
4. At times it will stumble at idle and die. Will start back up but has a dead peddle between 1,200 and 2,500 RPM
5. When warmed up it runs so rich it burns my eyes
6. There is no pattern, it either runs fair or keeps dying

I checked for codes and there are none. In bringing the car to a local mechanic he tried to scan it but no codes there as well. I changed the O2 sensor and it ran a little better for a short time. Fuel pressure is 40 PSI, I had to set the timing to 10 degrees or it would die.

I live in Arizona and there are no shops that work on this old stuff anymore. I don’t want to throw parts at it so any suggestions would be appreciated.

 

If I'm interpreting your statement

"Well gang I fell for the good old “ran good when parked” line and I’m at wits end."

You're saying you bought the car in this condition and have no record if it running properly beforehand?

when you say you checked for codes, did you do the paperclip in ALDL method? Or do you have a scanner?

If you don't have a scanner, I'd highly recommend investing in one. Given the age of these cars now and the propensity to break down, having a good scanner that can report out engine running data will help tremendously.

Unfortunately as is often the case with threads like this, there are dozens of things that can cause the symptoms. Without a good scanner and if the owner doesn't have a strong knowledge of how the EFI system works, they often times end up guessing and throwing parts at the car.

 

Yes unfortunately I bought it this way. I did the paper clip trick as well as had an OBD1 on it but nothing.

 

I don't know what you mean by "had an OBD1 on it but nothing".

Did you look at the running data coming out of the ECM? i.e, Coolant temp? Air temp? IAC counts? Injector pulse widths? Measured airflow reported by the MAF sensor?

These are the kinds of things that can tell you where to look.

 

OBD1 scanner didn’t show any codes. As far as the rest mentioned, I do not have the mechanical ability to do so.

 

You need to datalog if it’s mechanically sound it could benefit from tuning .
but I’d look at injectors first if there multecs replace see how it runs then tune for the cam .

 

My suggestion is yes since there are fewer and fewer shops that are willing to get involved you signed up for learning and doing a bunch yourself. Agree with Tuned, get a DVM and ohm the injectors cold and hot to see what you learn. You will need a way to monitor fuel pressure too even a cheap HF one for the time being.

Look for vac leaks.

This is a MAF car? Does it have the original ECM, do you know if the builder put in a different tune?

 

Even if you can't understand the running data on your own, if you can find a scanner that say, is able to output a .csv file that you can post here.

There are very knowledgeable people on the board who can look the file and potentially pinpoint the problem. Then over time you start to learn yourself.

Might be a couple hundred bucks, but probably will pay for itself over time as well as reduce frustration with the car.

Otherwise, even the knowledgeable people on the board, the best they can do is make wild guesses too, and you're back throwing money and parts at the car.

 

The 1985 model year TPI used an F-M output type MAF sensor. If is not interchangeable with any other model year, despite what many online sellers and even parts stores' catalogs may show. That has been documented here several times, including just recently. https://www.thirdgen.org/forums/tech...f-reading.html

A shop that has an older Snap On MT-2500 and the early GM configuration cartridge should be able to read live data, albeit at a very slow rate. The data may not help a "modern" technician solve the problem since too many are solely reliant upon the ECM/PCM data and are never adequately trained in actual diagnostic skill. Someone with a basic understanding of the system (very few of those remaining in the business) and a good multimeter would likely identify the problems.