I am currently having a problem with my 1989 5.7 TPI Iroc

MODS
Headers
Prom - tpi parts nothing special cutoff air pump cut off egr adjusted temperature settings injectors 22lbs
Moved fuel lines, replaced fuel pump and filter, new plugs, new wires, new temp sensors, new fuel pump relay, new tps, eliminated charcoal canister but left ufo think at fuel tank. Wrapped headers, exhaust and muffler, heated O2 sensor.

So finally have the car to stop boiling gas and recrank everytime I turn key. Followed all advice on overheating fuel so thst is good. However now it idles a little rough and surges in throttle up from mild to sometimes hard.

Read boards got a cable and downloaded program but now not sure how to read it. That was posted also quit guessing parts and scan computer so I did but I have no clue what a majority of this info is saying. If anybody could help translate and maybe offer a suggestion that would be great.

Thanks

 

Also forgot to mention new rotor, new dist cap and changed the ICM with a delco

 

I’m pretty novice at this seeing as how I started data scanning only a few months ago but a few things jumped out at me, looks like your running very rich with 108 BLM and INT not far off… do you have an adjustable fuel pressure regulator? You want to be near 128 on both BLM and INT ideally but there is some variance in that.

I will post a pic from my 88’ factory service manual to give you an idea about what factory cars should show on data scan. Hope this helps.



It can be a little vague but it’s something. Hopefully some of the guys who really know how to read scans can chime in.

 

The fuel pressure regulator is not adjustable. That is where I get.confused I am hoping someone can maybe suggest what or if they have had the issue and any suggestions on how to fix it. Thanks for the sheet do you possible have any ideas on what could cause it?

Thanks

 

I took another look and from what I can tell most of your readings seem OK except what I mentioned before with BLM and int , and the MAF readings look high, 12 GM/s at idle on a warm engine in idle is high, should be around 5.

I also have seen bad MAFs throw super rich readings of 108 BLM before as well. Might be worth looking at the MAF, any chance it’s a aftermarket one? These cars seem to like the Bosch oem the best.

What is the fuel pressure reading? I know it’s a stock regulator but just want to make sure it’s not getting to much fuel.

 

I am going to get a fuel pressure gauge today or tomorrow and see what it shows. I was thinking MAF I just was wanting to see if anyone else thought that could be it as well. It does change a little when I unplug it but i ma not sure if that is a real test the unplug test i am not ceratin but is is possible that it could be failing and not shoe codes? I would say i think it is possible to be right at that point before a code but when i get the fuel pressure readings i will post them

 

If you have a fuel pressure gauge and ability to data scan you are a step ahead when working on these TPI cars. I have seen 2 MAFs that did not function properly not throw a code. If you go aftermarket try Delphi or go with a used functioning Bosch. Are you running the factory ECM and prom chip?

 

Are all these screen shots at the same engine temp? Idle at the time 1k ?

 

Do you think he is in that ecm mode where the idle is higher than normal and fans are always on? I also noticed he is in 160 baud when 8192 baud would give faster and more info?

 

Could be left in 10k mode but iirc it’s only a 50-100 rpm adder

 

Ok so I did get a chip from tpiparts modified the temps for fan at 170-185, changed thermostat to 170 and fans switch from hawks at 170.
I also had the injectors set at 22lbs, Also cut off EGR and Air Pump and supposedly cut off the key thing but we tried another key and that did not work as expected.
I got an aldl cable from the one place and had to move the jumper around and it only gave me data in the .10 ohm position and the idle raised after that to 1000 when i unplug it it will go back to around 750 to 800
other than that nothing really been added or modified

 

it would only give data on the 10k it raised the idle

 

Should continue to datalog once 10k to initiate data flow. What injectors do you have ?
did angel change offsets ? If l98 already had a 22#hr flow setting. Maf does seem a hair high. Vacuum leak ?

 

Yes I had them leave injectors at factory 22 lb since it was an L98. I have so far not been able to find any vacuum leaks but will check again.

Thanks