86 svo runs rough at idle

[red766]

my 86 stock svo all of a sudden runs rough and struggles to idle. I sprayed engine clnr on it and changed all ignition components and now it is not driveable.... i put back the plugs, dist cap, rotor, and a new ignition coil with no change. the new wires are 8mm packard silicon....i hear the fuel pump running fine, .........it just runs rough and won't idle and isn't trustworthy...I removed the intercooler assembly and no change....any suggestions?

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any suggestions?

[RFranklin]

Did you check the ECU Codes to see any anomalies ? Also, did you check the TFI Module on the side of the distributor? My 2 cents

[red766]

I'll give it a try.

Did you check the ECU Codes to see any anomalies ? Also, did you check the TFI Module on the side of the distributor? My 2 cents

I'll have to buy an ecu reader. I lost everything in the wildfire and haven't replaced it all yet.

How do I check the TFI. Can I just unplug it and if no difference in idle/etc., then assume it is ok?

[red766]

unplugged and plugged

I'll have to buy an ecu reader. I lost everything in the wildfire and haven't replaced it all yet.

How do I check the TFI. Can I just unplug it and if no difference in idle/etc., then assume it is ok?

t
Not sure if this tells me anything....but I unplugged the tfi and the car wouldn't start, then i plugged it back in and it ran
rough just like before..... I did the same on the TPS, I unplugged it and the car wouldn't start and I plugged it back in and it
ran rough just like before.....

once I get a tcu reader, where do I find the codes definition.....?

[RFranklin]

You can find the code by using google or depending on the ECU Reader the can also display the code definition.If you are not aware our cars support the OBD1 interface located on the driverside by the ignition coil area. I also think someone posted the codes on this site. Try using search. In the meantime i'll try to download them and post a PDF.

[red766]

familiar with obd1.

You can find the code by using google or depending on the ECU Reader the can also display the code definition.If you are not aware our cars support the OBD1 interface located on the driverside by the ignition coil area. I also think someone posted the codes on this site. Try using search. In the meantime i'll try to download them and post a PDF.

I had an obd1 before the fire, and so I recognized the interface last night when I was fiddlin' with the car .

[RFranklin]

Diagnostic Code Sheet

Hope these can be helpful

Diagnostic Trouble Codes.pdf

[GAboySVO]

Check and clean the VAM.

[DRAGPAK]

I would also check out the iac to

[svono50]

The car should technically idle with the IAC unplugged, where it should drop idle to 750rpm. You would set the idle speed via the throttle body plate screw on the front of the throttle body. If the car is idling rough, it is either fuel or ignition related. I would check for vacuum leaks via a blown gasket or somewhere in the PCV system. The TFI module could be the culprit and the car will not start/run with it unplugged, so keep that in mind. I would not suspect the PIP in the dizzy, since they generally give you a warning before they go out and they flat out shut down the ignition system. Could possibly be a ECT sensor (located top center of lower intake) went out. If the EEC loses that signal it defaults to a very, very cold engine temp and runs really rich, which can foul out your idle if it doesn't race up to 2000 rpm. Even with the fuel pump running, you may have fuel pressure issues. What do the plugs look like (i.e.- dry, fuel fouled, oil fouled, etc)? Outside of that check your compression to see if the head gasket decided to give up the ghost. Sorry for the rambling, but there are many potential issues.

[stockman1]

Sounds like you knocked something off? Check visible connections and make sure plug wires are not reversed. Look for vacuum leaks & check the coupler between the VAM and turbo. Move the duct with the car idling and check for changes in idle speed and quality.

[red766]

firing order iss 1342 clockwise right? did code scanner and got 21254177....if 2 digit then 21 25 41 77.......

where do I find the knock sensor? thx to all for help,...I'm missing driving the car...

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guess i gotta pop the top, watch the valves to make sure rotor is lined up for #1 firing.

[GAboySVO]

Code 21 is your issue. The ECT is out of range and will cause poor idle. Check to see if you knocked the connector loose when changing the wires. If the connector is fine, then replace the sensor. It is located in the center of the lower intake near the fuel rail.

Her are the other codes:

25 Knock sensor not tested (ignore if not pinging)- not your issue

41 (R) System lean
(M) System was lean for 15 seconds or more (no HO2S switching) - probably caused by the ECT issue

77 System did not receive "goose" test - you did the test wrong or couldn't rev the engine due to the ECT sensor problem.

[svono50]

I have to agree with Mike, the ECT can really foul things up for idle and part throttle cruise when the EEC is looking for it. Make sure all your harness connections around the intake are seated an also along the firewall behind the intercooler, where you could have bumped one with the ignition work. Here is a picture showing the little bugger that I found in my stash of pics. Don't go for one of the all plastic models, mine didn't last me 1 full season before giving out, I suggest a brass body one like in the picture. Good luck.

Sensor - ECT_Lower Intake.jpg

[kiwi]

That engine bay way too clean Ted......