Very high reving until come to stop...

[Dr76]

'93 2.3L 5-speed... recently started reving very high (don't have a tach, but estimate in the 2,500 - 3,000 area) and doesn't come down until I'm almost at a complete stop.

Scanned it and getting a few Ignition faults (223 - Dual Plug, SPOUT or IDM circuit fault, and 224 - Failure in ignition coil primary circuit), but thought I'd see a either a VSS or Cam sensor fault...???

Suggestions???

 

[stikman]

high revs

First thing that comes to mind is the TPS. Try setting dle down a little and see what happens. Put a meter on it at the TPS while running and set the idle until it reads just below 1 volt if I remember it right.

 

[Bryan22]

the codes point to a bad coil, bad ICM or a bad ground somwehere, but you'd notice more driveablility issues if something was really wrong. I would blame the high idle on a gummed up IAC, which can easily be removed and cleaned for the price of a new gasket. it wouldn't hurt to get out there with a multi meter and check the resistance on the coils though. Also your 93 dosen't have a cam position sensor. And if you want to clean up the connection to the VSS it's the plug going into the tranny alongside your speed-o cable. also the TPS i beleive it's supposed to be .70-.90 volts at idle and constatly increasing to 5 volts at open throlle, with no dead spots. don't quote me on that though, just off the top of me head. If you do a search it's been discussed a few times.

-bottom line, i'd try cleaning the IAC before anything else. good luck -

 

[fastpakr]

I'd definitely clean the IAC, but that's not your only problem. I can try to scan the relevant pages out of the Mitchell manual for 223 (start with that, then move to 224 if it remains after you fix it) but it may be Monday before I get the chance. The obvious checks are ensuring that you have power to each coil, check the primary and secondary resistance on each, then verifying the wiring from the coils to the ignition module and the ignition module to the ECU.

 

[rich58]

I would check your idel air control valve first.

 

[fastpakr]

The IAC is not remotely connected to an ignition fault. It does sound like it needs be cleaned, but there is more than one issue here.

 

[Bryan22]

+1 I got those same codes. turned out to be a bad ground and a bad coil. but i had way more problems than just a high idle. suprising he's not having any other problems with it throwing those codes. yours ended up being a bad ICM right fast?

 

[Dr76]

WOW, thanks for all the replies... I will definitley look into ALL of them (hopefully this weekend).

Those 223, 224 codes come and go. I delete them and they come back every once in a while (sometimes a few days, sometimes a month or so). The "fast idle" just appeared out of the blue, but *ALL* my issues will be looked into.

I'll post when I have some findings...

Have a GREAT Holiday weekend!

 

[Dr76]

Update (part 1)

Didn't have a chance yet to do all the tests that were recommended, but I have cleaned up the IAC and the high-rev issue seems to be fixed (THANKS!)

Now for the coils... I checked primary and secondary resistance, but want to be sure I did it correctly:

Primary: There's 3 terminals (pins) on each of the two coils (the middle one being "B+") I put one of the meter leads on the "B+" terminal and the other lead on each of the other two terminals and got ~ 1.0 OHM for all (bounced between 0.9 and 1.1)

* The documentation I have states that this is HIGH, but in limits.

Secondary: I put one lead on plug tower #1 and other lead on #4, and then one lead on #2 with other lead on #3. All results were in the 15K OHM range.

* Documentation states that it should be between 6.5K and 11K OHM.

Is this the correct way to test???

Thanks!

 

[fastpakr]

Both of those numbers are fine. The secondary resistance numbers seem to vary by source, but yours are definitely within reasonable parameters. I'll grab my Mitchell manual tomorrow and get the next tests, but I'd suggest you can start by verifying power to both coils and then testing resistance between them and the ignition module. If that tests good, it's pretty easy to pull the module off and have it tested.

 

[Dr76]

fastpakr, THANKS for your patience! I've got a few projects going on and not able to spend nearly enough time on ANY of them to actually finish one! : (

Anyway, I have verified "B+" voltage at each of the two coils. As fas as testing resistance between them and the ignition module, I'm not sure what the testing procedure would be... so, if you could point me in the right direction, that would be great!!!

* and going back to my other issue of "fast idle" (which seems to be OK now), I have checked the voltage at the TPS and it seems to flow pretty smoothly from 0.922V - 4.69V at WOT w/o any "dead spots". Hopefully that issue is resolved.

Thanks!!!

 

[fastpakr]

You'll have to get a little bit creative following these, as you obviously don't have the diagnostic and breakout equipment it refers to. However, it's pretty straight forward to infer which wire it's telling you to test on each end, and you can use the wiring diagram to double check the color so you know you've got the right one. For what it's worth, if you have an Advance Auto or similar nearby, they should have the equipment to test the ignition module directly and it's at least reasonably possible that's your problem. I'm not suggesting you replace it without testing, just that it might be worth pulling and taking it to them to check before you spend too much time looking back and forth at diagrams and wiring. In any case, attached is all the information you should need...

 

[fastpakr]

Paraphrase of testing procedure for normal home use:
1) With engine running, measure voltage between SPOUT at ignition module and battery negative. >2 volts go to step 2, else go to step 6.

2) Check for spark at each left side plug wire with engine running. If spark exists on at least 1 wire, replace ignition module and run codes again. Else go to step 3.

3) Turn ignition off and disconnect wiring harness to computer (drivers side against the firewall). Measure between DPI pin at computer harness and DPI pin at ignition module harness. If < 5 ohms, go to step 4. If not, there is a break in the DPI wire between the ignition module and computer. Locate and repair, then run codes again.

4) Turn ignition on and measure voltage between DPI pin at ignition module and battery negative. If < .5 volts, go to step 5. If not, DPI wire is shorting to ground. Locate and repair, then run codes again.

5) Reconnect computer wiring harness. Connect a test light between DPI pin at ignition module and battery ground. Start engine. If light is on, replace engine computer and run codes again.. If off, replace ignition module and run codes again.

6) Turn ignition off. Set volt meter to AC, then measure voltage between SPOUT connector at ignition module and battery ground while cranking engine. If > .1 volt, replace ignition module and run codes again. Else go to step 7.

7) Turn ignition off. Set volt meter back to DC and disconnect wiring harness to computer. Turn ignition on. Measure voltage between SPOUT connector at ignition module and battery ground. If > .5 volts DC, SPOUT wire is shorting to power between computer and ignition module - locate, repair, and run codes again. If .5 volts or less, replace engine computer.

 

[Dr76]

Excellent info... THANKS SO MUCH! I've had other projects take precedence, but, hopefully, I'll have some free time soon and be able to go thru these procedures.

I'll post my findings...