Hi,
I got a problem with rough idling. I've changed sparks, cables, coil, distributor cap and nothing has changed with idling. So, I've recorded some data with DataMaster. But know nothing about what DataMaster is telling me. Is there anybody who could take a look at my data file and tell me what is going on?
The car is stock (probably) T/A'91 5,7L.
Thx in advance

 

Where is the data??? //RF

 

Here is the file. Hope it's OK.

 

Bulbon

I took a look at your data log by playing it back and extracting idle section of the data log.

It appear that your engine is running very rich most of the time. For the most part your CL idle BLM are in 108-110 range which means that ECM is trying to remove fuel based on O2 sensor cross counts. To compensate for rich mixture ECM is trying to keep IAC open - allowing additional air to enter intake manifold. Your idle IAC counts are way too high in the 65 to 70 counts. I would expect more like 5 to 15 counts. ECM is making a valiant attempt to keep fuel mixture in the prescribed range (14.73:1), but it it is railing out - by removing fuel (15 to 20 percent from base line). High BLM's are possibly due to leaky fuel injector(s).

Do you have stock injectors?


//RF

 

Probably the injectors are stock. I've bought the car 6 years ago and I haven't change them. The idle was rough from the beginning. But now it is getting worse.

 

Check plugs and wires to see if all cylinders are firing. A dead or a misfiring cyl will cause a rich condition. However TPI injectors are known to go bad with age.

//RF

 

Ok, thx. I'll let you know when figure out what is going on.

 

By the looks of it, we have similar problems. My BL starts dropping as soon as closed loop starts. IAC counts at idle are around 70 - 80 range.
Mine also now acts like it has developed a hard miss so its time to pull and read the plugs. And I confirmed my 1-8-4-3-6-5-7-2 order last night. Don't forget to re-sync the IAC too.

 

If the injectors are bad, I would go with the Bosch III modified from Jon at FIC, They have exellent spray pattern and they are flowmatched (each set) and he leaves 3 years warranty on them, costs 169,95...

http://fuelinjectorconnection.com/sh...&productId=134

Get your injectors checked, bad injectors can cause alot of things. Call Jon up and he will help you out

 

Be sure and measure the resistance of your injectors. The manual states "10 OHMS or more". I have 4 that measure 16.5, 1 that measures 12, One that measures 7.5 and 2 that measure 5.1 !!!! The LOW OHMERS will load the injector drive signal down for the entire BANK and will foul up the mixture control. I am injector shopping now. Let us know what you find. And Thanks Theking!

 

shingadaddy, youre welcome
talk to Jon then and he will fix you up with some good injectors

and keep us posted.

 

Much appreciated. I am going to check a couple of local places here in Tulsa and see what they have. I noticed those are rebuilt units but if they work and are warrentied, this is good.. Checked my compression last night since I already busted my knuckles getting the plugs out. 190 to 195 on all. Pretty happy with that!! My thread is the newbie thread regarding my stuff but no one responded to my questions. This board has some really old and outdated stuff on it too. Looks like the admins / moderators / big board kahoona's have taken a hiatus. Thanks for replying. Maybe Bulbon will let us know how his adventures go.

 

Just ordered the injectors from Jon at fuelinjectorconnection.com. He said mine are supposed to be 22LB injectors. This is what he is sending. My injectors look black on top and green on bottom. Some time ago I read where the injector could be identified from its color. Mine appears to be like the DELPHI units that are on their website but he units I am getting are the BOSCH Gen III. Can't wait to see what goes on next but it will be next week.
Thanks again Theking.