opelbits

iTrader: (5)

Did some searching, no help.

I have a 90 non-turbo with an ignition problem. The leading coil fires ok (spark drops out sometimes) at low rpm, but at 3500+ the timing light shows zip, no flashes.

Trailing coils fire nice all the time, no drop out.

Plug wires are good, coils are good, new plugs.

Any clues? Crank angle sensor maybe?

RRTEC

iTrader: (13)

Having the same problem but in the reverse order, my leading are ok the trailing are going out at high rpms...Would really like to know, I replaced the ecu and the problem went away but the ecu fryied in 6 hours so there has to be a reason it went out in the first place..

let me ask you this..

is the car hesitating bad?
does it afterburn (pop pop pop pop) on deceleration
Is your idle rough like the motor shakes around a little?
is your tps unsetable ie, surges often sweeps past 5k at wot?

silverrotor

iTrader: (1)

Are you running an Ignition Box with your setup? I know with older Spark Plugs (although you've said yours are new) and with the Ignition Box, several have had print outs of erratic readings with anything over 5000 rpms on the dyno - myself Included.

HAILERS

TAke the trailing plug wires off and lay them to the side. Start the engine. Rev the engine. Did the engine die above 3500rpm?

Josepi

Just curious where you're headed with that line of thought!

opelbits

iTrader: (5)

No hesitation, but there was a noticeable lack of power above 3k, almost like secondaries and 5th-6th ports were non functional.
Was popping before (all the time, got worse as rpm increased) but swapping coils/plug wires got rid of 99% of it.
Was shaking the motor quite a bit, now it is just slightly and has much more power.

Haven't adjusted TPS. Sometimes it will cycle between 800 to 1300rpm. Not often, just once in awhile.

Everything ois stock, no ignition boxes.

I did accidently start it with the leading coil harness connector unplugged, car died pretty quick. I'll try taking the trailing wires off tomorrow (since you said that, it makes sense to try it given my symptoms. But, of course, it didn't even occur to me last night).

To test all this, I took the coils/wires out of my driver (87 GXL). I checked that car before removing the parts. With a timing light on each plug wire the timing light was steady and consistent regardless of rpm.
After installing everything in the 90, it made the improvements noted above, but it loses leading spark pretty quick.

RRTEC

iTrader: (13)

bump

RacerXXXXXXX

This is to both posters, the 1 with the ecu frying, and the other with ignition problems...

The leading ignition ignitor/coil unit has to have a good ground (from the metal backing), as well as a good + signal from the battery but that is internal to the ecu, bad grounding at the ECU can cause the ECU to go bad cause it will strain the components trying to find a ground. Same as having too low a guage wire on an amp, you will fry the amp, or the wires going to it.

Having a fried ecu, you could take it apart and find the bad components with a cheap multimeter and a soldering iron and solder wick .... that would tell you what is giving you issues ...

As for the CAS being bad, if your trailing fire and the leadings dont ... its not the CAS .... when the CAS is bad, it wont fire any coil because the ecu never knows when TDC of anything is ... I would look at lack of power requirements of the coil ... (bad grounds or wiring) if they check out ... then you could have a bad water temp or air temp sensor that is causing the fuel mixture to be too rich and not fire on the plugs cause they get soaked. Are you having any problems with fouled plugs?

If its not those two sensors, then you could have a leaky fuel injector, you can swap for some known working ones but Fuel injectors are strange, even sometimes when they come from a working motor, when they sit out for a while, sometimes they just "stop working as intended" so, I would recommend doing a swap in a day or less ... or, send the injectors off to some place liek rc engineering and get them cleaned and balanced ...

Last thing is fuel pressure and FPR on the secondary rail, check fuel pressure if you can and veryfy 40ish at idle, if your fuel pressure is low you would be able to start you car but it wouldn't free rev without ALOT of backfires ...


Hope this helps

opelbits

iTrader: (5)

Well, I think an update is in order...

Lesson #1: Make sure your timing light is operating correctly! It seems the timing light I used the other night has 'issues'. Doesn't really change any of the symptoms, but it does make it harder to diagnose.

Lesson #2: Just becuase you fix something, it does not mean you are getting any closer to your goal. Tracked part of my problem (popping/misfiring, low mid-upper range power, high hydrocarbons during emissions test: .8 grams pre mile is the standard, first test was 1.7 gpm (failure). New plugs netted me an increase in hydrocarbons (2.3gpm). Replaced the 'odd' coils and plug wires with my driver's coils and wires. MUCH better running. No popping, no misfiring, more low end power, exhaust does not stink anymore. Emissions result? 3.5!

Runs good, though.

I'm thinking O2 sensor and cat issues.....

opelbits

iTrader: (5)

Hailers-
The results of the trailing wire test you suggested are incomplete. I removed them and did as you said. I did not rev the engine as the noise from the 'sparking' was worrisome. I didn't expect to hear all that 'snapping' as the coils fired and it jumped. I understand that is a bad thing to have in a car with sensitive electronics.

HAILERS

The reason I asked you to remove the trail plugs and rev the engine was to prove to you that the LEAD plugs were not dropping out.

Any number of times I've read on this forum where they say that their lead plugs/coils are firing erratically, when it's just a timing light issure. Usually you can take the clamp on the plug wire and reverse it and then the timing gun will show a consistant firing instead of an irregular firing.

There is a factory service bulletin that addressed this *timing light* problem. ALLDATA.COM has those factory service bulletins.

If your having emissions problems.......check out your acv system, since you've replaced the plugs and set the timing. Also set the idle per the fsm i.e. install the initial set coupler etc and make the adjustments.

HAILERS

My post directly above is where I was going.

opelbits

iTrader: (5)

Hailers-

One of the things I checked on the timing light was to look for the "This side towards sparkplug" markings, but I found none. The reason I initially thought the leading coil was not firing correctly, was because the very same timing light showed my driver to have consistent spark with no drop out all through the rpm range.
Then, when I swapped coils and wires, the popping and misfiring went away. Between the two, it made sense (except for the fact the leading coils seemed to drop out above 3500rpm). When I checked it with my timing light, there was no more drop out. Which implied a timing light issue.

I didn't set my timing at all. We were using the light to check for consistent spark and to determine which plug or plugs were not firing correctly. If it was ven a spark problem. The idle speed is fine, it is at around 800. Every once in awhile, like maybe, once every third or fourth day, it will do it's cycling thing, but only for a minute or so.

opelbits

iTrader: (5)

Lesson #3: Whatever you think it is....that's not all that is wrong. Took a reading on the 02 sensor. Zip, zero, nada. Replaced 02 sensor. Still zip. While trying to figure this out, I found that the forward auxiliary port (5? 6?) is stuck closed. Rear port is just fine. I have a feeling this may have something to do with my lack of power above 3500 rpm.
Soooo, it looks like I have to disassemble and clean the 5th and 6th ports before I can determine anything on that front. In the meantime, I have an 02 sensor not sending a signal to figure out.

Cwaters

Too much anti-sieze, not allowing the sensor to ground to the manifold???

Just a guess

HAILERS

About the 02 sensor....try this. Get a meter out. Disconnect the 02 sensors plug at the 02 sensor (where else). Put the positive lead on the output wire and the neg on the SIDE OF THE 02 sensor. Did you get a reading/output???

And if your car is a normal car with all its parts still attached (like the airpump and acv)then try the same as above but.......remove the BLUE plug from the Relief Solenoid. Did you now get a reading???? You should have (car running of course).