Ignition Problem...I think...?

[DSMGary]

Hi All,

I am having a problem with my ignition (so i believe). To start off the engine was stumbling during load. I figured that its time for the wires and plugs to be replaced. Parts are OEM. Infact my entire car is oem (no mods). Replacing the plugs and wires did not help much. Afew days have gone by now and the problem is even worse...horrible idle and missing thru idle and driving speed. Thus far i have checked the following:
Igntion coil primary - less then 1 ohm
ignition coil 2nd - 12.6Kohm
TPS - resistance thru range is normal, and normal @ closed also.
ICS - with throttle fully closed i get continuity, No cont with open.
Fuel injectors - all 4 are @ 3ohm (and they make a nice clean consistant ticking sound.

Decided to outrule the fuel delivery so i placed a timing light to each spark wire, found that there is a miss on all 4 wires, but it is random...

Also checked diagnostic codes. Found no trouble codes, ECU shows normal state.

I am all out of ideas now... PLEASE HELP.

 

[LKWTSI]

Have you done a good Boost Leak test. sounds like something maybe leaking. If in fact your car is OEM and no mod's, I'd suspect a leak in the rubber intercooler pipes or vacuum lines.

Try this first and see if you can solve it from this if not then you can start looking at more complex things.

IC Pipe Tester

 

[And_44]

I'm having a very similar issue. I recently went out and bought alot of known good used parts from a car that had a broken T-belt but ran before that happened. Things I've replaced are plugs, wires, ignition coil, ignition module, MAF. Things I've tested ISC (cold), TPS, o2 sensor. The ISC/TPS I'll be replacing the whole Throttle body assembly with the known good used ones tomorrow. The o2 sensor tested was weird and was a steady reading but will retest when other parts are replaced and I get the exhaust manifold leak fixed. I've got a CAS to swap out if the ISC/TPS don't work, then if push comes to shove I got a 2nd ECU to throw in.

I'm hoping it's the TPS/ISC going out as the problem happens when the car is hot. The symptoms are also signs of a failing ECU but I believe the ECU would make the problem happen through out the driving temperature range cold/hot.

Well, sorry if this doesn't give you the golden answer but at least it can give you a better idea of what to look at, test, swap, or replace.

 

[euphoria]

Check the connection on the ignition module, when it gets loose the car will act very strange.

 

[And_44]

Yes, the loose connection could also be a very likely problem. But if you have it secured firmly where it should be it's not likely.

Could you use the electrical grease in the connection area? I've noticed that the 2 modules I have the copper pins have got some corrosion building up on the connectors.

When the car starts acting up and misfiring I can remove the module clean the connectors let it cool and reinstall and car runs fine though till the module heats up again.

But the problem can be something else that easily heats and cools like the module, like the TPS/ISC, CAS, and symptoms of a failing o2 sensor.

I'm just waiting for the autoparts store to open to get some gaskets to replace my throttle body with another with a known good TPS/ISC.

I'll keep ya updated.

 

[DSMGary]

Have you done a good Boost Leak test. sounds like something maybe leaking. If in fact your car is OEM and no mod's, I'd suspect a leak in the rubber intercooler pipes or vacuum lines.

Try this first and see if you can solve it from this if not then you can start looking at more complex things.

IC Pipe Tester

Hey thanks LKWTSI.........checked for boost leak finally... not a leak.. system is tight... Any other ideas... I am getting frustrated with it now...

 

[And_44]

I fixed my misfire;D My alternator wasn't putting out enough voltage to my coil pack so was getting no or low spark to cylinders.

Replaced Alternator and going onto day 3 with not a single misfire.

 

[LKWTSI]

Hey thanks LKWTSI.........checked for boost leak finally... not a leak.. system is tight... Any other ideas... I am getting frustrated with it now...

Sorry it didn't help.

I guess maybe to help narrow down the cause, can you describe exactly what you mean by "horrible idle" and "missing thru idle". Is the "miss" constant at one RPM range or different ones. Also, is the idle surging? Does it go away after the car warms up, get worse as the car warms up?

Also, you may want to try this and see if it's something to eliminate or cure your problem.

http://www.dsmtuners.com/forums/articles-electrical-wiring/229419-how-test-power-transistors.html

Good luck and it'll show up eventually.

 

[DSMGary]

Sorry it didn't help.

I guess maybe to help narrow down the cause, can you describe exactly what you mean by "horrible idle" and "missing thru idle". Is the "miss" constant at one RPM range or different ones. Also, is the idle surging? Does it go away after the car warms up, get worse as the car warms up?

Also, you may want to try this and see if it's something to eliminate or cure your problem.

http://www.dsmtuners.com/forums/articles-electrical-wiring/229419-how-test-power-transistors.html

Good luck and it'll show up eventually.

okay...more details... the Horrible idle is a result of the misfire. The idle is stable and does not jump around...the idle is @ 750-800 (cause of the mis, u can see the tach deflecting abit). The only thing consistant about the mis is that it does it thru the entire rpm range... i took it up to 4000rpm...iam sure that it would do it higher... just didnt want to crank it that high with out load on engine...nobody wants to spin a bearing.. The miss is present at all temp range...from cold start to hot temp with rad fan toggling on/off. Will test the pwr-X-ister

Anything else u can suggest i should try?

 

[And_44]

Hi All,


Decided to outrule the fuel delivery so i placed a timing light to each spark wire, found that there is a miss on all 4 wires, but it is random...

Also checked diagnostic codes. Found no trouble codes, ECU shows normal state.

I am all out of ideas now... PLEASE HELP.

I was having same issue, when I replaced my CAS with another and went to adjust my timing with the light I wasn't getting signal in the wire, meaning not enough power was going through wire to cause a spark and there for getting a misfire.

Is your alternator the original OEM one as well? Our alternators have an internal voltage regulator and it could be faulty and not sending enough power to your coil to ignite the plugs.

 

[LKWTSI]

I know you've said you checked the CEL's and none where evident, BUT can you get your hands on a logger and do a couple of pulls and see if something stands out on the logs.

The fact that you don't have a CEL, just means the ECU hasn't been supplied with enough information or interpreted the fault to a degree that it would recognize a faulty component. Doing a log will allow you see exactly what might be triggering the "miss" and help point the finger in the right direction.

 

[DSMGary]

I was having same issue, when I replaced my CAS with another and went to adjust my timing with the light I wasn't getting signal in the wire, meaning not enough power was going through wire to cause a spark and there for getting a misfire.

Is your alternator the original OEM one as well? Our alternators have an internal voltage regulator and it could be faulty and not sending enough power to your coil to ignite the plugs.

Hi And_44, That was something i had not checked. When i measured the battery voltage while the car was running, i was getting 12.6 VDC and when i revved it up about 2K i was getting 13.3 VDC. Looks like i am not getting enough "juice" from the ALT. Will be pulling it out soon and sending it out for a rebuild. Will let you guys know of the progress soon!

 

[DSMGary]

Hi And_44, That was something i had not checked. When i measured the battery voltage while the car was running, i was getting 12.6 VDC and when i revved it up about 2K i was getting 13.3 VDC. Looks like i am not getting enough "juice" from the ALT. Will be pulling it out soon and sending it out for a rebuild. Will let you guys know of the progress soon!

OKAY.... Rebuilt ALT... rectifier was bad... Still have the problem... what gives? So whats next? I am starting to not like my car anymore

 

[And_44]

Have you checked your fuses by chance? The ones in engine bay and under dash. How old is your coil? It could be arcing and you loosing the spark. Is the misfire seem like 1 cylinder? Or two for example 1&4 or 2&3? 1/4 and 2/3 are each from the same coil on you pack and if it's the 2 misfiring I'd look at your module. It its one that's random may be a leaking coil, or just not enough juice hitting the system. You rebuilt your ALT so go to the next step in that chain for power supply. Fuse's.

Worst case is your ECU is taking a poopoo on you. It may sound, look and smell good but see about swapping it with another from a local to rule that out.

I have 2 ECU's and both look great. I have one running the car, but the other one heats up and cause's massive misfire, believe it was my failing ALT that did it to that bad ECU.