my truck runs like crap

[RockRanger]

I have an 86 ranger 2.9 4x4 5spd 4.10s on 33"s. what it is doing is haveing a very high idle all the time. I turn the key on-off a few times and the idle will come back down for a few minutes then creap its way back up. It also doesnt have very much power for climbing hills. I have one of those $30 code readers from wal mart and from that it is giving codes of 18 (Spout open or SAW circut failure or loss of tach input/ IDM circut failure/ spout circut grounded), 22 (MAP or BORO sensor out of range), 63 (Throttle posision circut fault below minum range), 33 (EGR valve not opening properly) . These are all when the motor is warm key on engine off. Do these make sence before I go out and buy a bunch of parts. Also I have a spare 2.9 out of a 90. Will any of these work on my 86. Part of teh efi on it looks different then mine so im not sure if they will swap or not. Thanks for any help

Matt

 

[Runnin'OnEmpty]

Matt, you may have two or three problems at once on this one. It's running poorly because of the SPOUT/IDM fault. That is 'probably' because of a bad ICM (ignition control module). They're famous for going bad on the BII's.

You can check the TPS voltage with a multimeter, if one is available. Do a search for the procedure; basically you are looking for a smooth transition from 1v to 4v on the TPS signal wire when the throttle is advanced.

The MAP/BAP is probably bad. Try spraying it with WD-40 along with the connector, and see if that improves anything.

The EGR valve could need cleaning, or the sensor mounted on top of it could be bad. Try swapping out the one on the 90......

The ICM should be the same on both model engines. If the TPS and MAP/BAP sensors will fit, try swapping them also. Good luck.

 

[RockRanger]

Thanks for the info Ill hopefully get to mess with it a bit tommorow night and see what I can figure out.

On that ICM I had one go bad a year ago (that was the one on the truck when I bought it 6 years ago) Then 4 days later the new one went out. The one I replaced the second one with is still on the truck. Granted in the last year my truck has maybe seen 3000 miles of driving . Trying to get it ready to go wheeling in 2weeks so I need it running half way decent. The crappy idle and what not started a while before the ICMs went. What would cause them to keep blowing. Should I maybe change something else as well.?

 

[Runnin'OnEmpty]

Ranger, there's a pick-up coil inside the distributor that most mechanics change out along with the ICM. I don't know if one will cause the other to fail or not, but they are often changed as a pair.

It's very important to use grease on the ICM base where it contacts the distributor. This helps to cool it, and heat is what causes most to fail.

Concerning the EGR, you can disconnect the vacuum hose temporarily and plug it, and see if that makes a difference......

 

[RockRanger]

update on my truck.

1st found a ground wire that went from teh drivers head to the body by the widow wiper window was broken. Replaced that with the one off the 90.

Then went to try swapping the TPS sensor off the 90 but the plug on the end is different. I did mess with the one that was on there a bit with my digital volt meter. I think something is broke in my volt meter but when on the resistence setting I was able to get it to move off of open as I moved the thorttle. So I think that is working right but Ill be going and buying a new volt meter tommorow.

Then replaced the thing hanging off the upper manifold on teh passanger side not sure what it is (any ideas) dont know if it helped or not but the one on my truck seemed to have a bunch of oil on where the one on the 90 didnt so i changed it.

Then I checked teh EGR valve( thing under the throttle) with the motor running pulled the rubber line thing off teh front of the valve and could feel exhaust coming out. then put that one back on and pulled the one off the back no vacume or suction on eather side. So I pulled the valve off the truck. there was no way to blow between the part attached to the exhaust and the part hooked to the intake. So I think that it is clogged. There isnt one on teh 90 so Ill go buy one tommorow. When i started it with the egr off the rpms shot to 4000 rpm but could feel exhaust coming out the tube.

After all this it still idles high but doesnt seem to have the stuble off idle it had hopefully that was caused by the missing ground wire that is now installed. tommorow Ill get a new egr valve and volt meter replace teh egr check the TPS and see what happens from there.

Matt