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So, tonight, in the middle of driving home from college, my car just decides to start acting weird. I was driving a long at ~55mph and I suddenly get a really bad shake from the engine area. Lo and behold, if I keep the RPM's up, the shake goes away, but under further inspection, it's just a cover up.

I pulled into the grocery store parking lot I was headed toward, and I put it in neutral to rev it up, to see if it would clear out. Well, it didn't clear out. Instead, it just runs like crap. I can hear it hitting and missing and what not and during the neutral revs, I thought I heard it backfire a few times. Definitely signs of what my MAF did back a few months ago. It's weird because this was my 3rd trip (as in trip to one place) and it was in the middle of the trip that the car started acting weird. Before that, I was holding with an STi (he was making good time) and I had absolutely no problem (as in engine acting wacky).

Is it another MAF? I have no posted codes, and I'm clearing the ECU tonight to make sure that that isn't the issue. Could it possibly be anything else? In the last shot, I replaced MAF, Knock, and CT sensors. So, assuming that all of those are good except maybe a toasted MAF, that doesn't leave very many sensors left to replace.

::EDIT:: Reset ECU and it's still hacking and crap. I really don't want to pay for another MAF - I don't think I'll get a deal like I did before.

Manarius wrote:So, tonight, in the middle of driving home from college, my car just decides to start acting weird. I was driving a long at ~55mph and I suddenly get a really bad shake from the engine area. Lo and behold, if I keep the RPM's up, the shake goes away, but under further inspection, it's just a cover up.

I pulled into the grocery store parking lot I was headed toward, and I put it in neutral to rev it up, to see if it would clear out. Well, it didn't clear out. Instead, it just runs like crap. I can hear it hitting and missing and what not and during the neutral revs, I thought I heard it backfire a few times. Definitely signs of what my MAF did back a few months ago. It's weird because this was my 3rd trip (as in trip to one place) and it was in the middle of the trip that the car started acting weird. Before that, I was holding with an STi (he was making good time) and I had absolutely no problem (as in engine acting wacky).

Is it another MAF? I have no posted codes, and I'm clearing the ECU tonight to make sure that that isn't the issue. Could it possibly be anything else? In the last shot, I replaced MAF, Knock, and CT sensors. So, assuming that all of those are good except maybe a toasted MAF, that doesn't leave very many sensors left to replace.

::EDIT:: Reset ECU and it's still hacking and crap. I really don't want to pay for another MAF - I don't think I'll get a deal like I did before.

well was this MAF new or used? Did u get it from a local parts store or dealer? or internet? because possible if it is from local parts store then they usually sell remanufactured goods, or there own branded junk.

could have timing belt jumped a tooth....
could have a bad plug wire, or coil going sour, etc.

you know whats weird is my timing belt had three teeth missing, and the car ran real good, i found out when i went for my maintenance timing belt change, and the guy told me it jumped 4 teeth? i dont know why the car ran pretty good, but definitly felt better after timing belt change, but sitll!!! thats pretty darn good if what he said was true.

Freakin' a. So, I replaced the sensor - still ran like hell. Drove it back home - during the middle of the ride, the car decided to start running correctly again. Now, with the Hitachi sensor 55BCTurbo sent me, I have a CEL 49 code, but the car runs like it's brand new. Resetting the ECU has no effect on the code. Think I should just drive it around with the CEL on? Or is there a way I could trick the ECU into thinking it has the right sensor?

Another interesting thing: My dad in his infinite wisdom wanted to make sure the car was firing on all cylinders. So what did he do? Pulled the plug wires at the coil to check the arcs. When he pulled the plug to #3, the car didn't do anything at all. Like, it didn't run rough or anything. When he pulled the plug to #2, it didn't run quite right, and when he pulled the plug to #1 or #4, the car ran like hell. Is that indicative of something?

Manarius wrote:Freakin' a. So, I replaced the sensor - still ran like hell. Drove it back home - during the middle of the ride, the car decided to start running correctly again. Now, with the Hitachi sensor 55BCTurbo sent me, I have a CEL 49 code, but the car runs like it's brand new. Resetting the ECU has no effect on the code. Think I should just drive it around with the CEL on? Or is there a way I could trick the ECU into thinking it has the right sensor?

Another interesting thing: My dad in his infinite wisdom wanted to make sure the car was firing on all cylinders. So what did he do? Pulled the plug wires at the coil to check the arcs. When he pulled the plug to #3, the car didn't do anything at all. Like, it didn't run rough or anything. When he pulled the plug to #2, it didn't run quite right, and when he pulled the plug to #1 or #4, the car ran like hell. Is that indicative of something?

it's normal for our cars to act fine at idle with cylinder 3 down.

the proper way to check and see if Cyl 3 is firing is to pull the plug and inspect it for fuel fouling.

edit: also since we're on a wasted spark setup and 1/3 are tied together, if 1 is firing, 3 is firing unless you have a bad plug or plug wire or coil post (not likely on the coil post) - The reason why our engines are damn near undetectable when they're only running on 1,2 and 4 is due to the firing order and the location of cylinder 3 - IIRC.

scuzzy wrote:it's normal for our cars to act fine at idle with cylinder 3 down.

Please explain this logic?

it's normal for our cars to act fine at idle with cylinder 3 down.

Yes this dosent make any sence, the nature of a boxer engine, with it haveing very little counterweight in the rotating assembly means that if any one cylinder isn't fiering the engine will most likely want to jump out of the car!

Back onto topic, did you hear the plug wire arcing when he pulled it off? If so I would lean twards a clogged or clogging injector or maby an intermitent electrical short/open in the #3 Injector harnes/circuit. If it wasn't arcing check continuity of the plug wire.

Legacy777 wrote:

scuzzy wrote:it's normal for our cars to act fine at idle with cylinder 3 down.

Please explain this logic?

was that way on my old EJ22 engine IIRC, havn't tried pulling the plug wires off on the EJ22T yet because I haven't needed to.

Anyway, don't take my word for it, go try it, think it works the same for everyone and I'm pretty sure #3 wasn't down in my car because the plugs looked fine when I pulled them at regular intervals.

YMMV.

I've done it to, and it didnt really change the idle, although it was idling like crap anyway so that may have masked the effects of losing Cylinder #3.

Thats just my experience though, try it for yourselves! .....or don't, I wouldnt really suggest it actualy...

subytech wrote:Back onto topic, did you hear the plug wire arcing when he pulled it off? If so I would lean twards a clogged or clogging injector or maby an intermitent electrical short/open in the #3 Injector harnes/circuit. If it wasn't arcing check continuity of the plug wire.

Well, he pulled the plug at the coil and I saw it arcing (scared the crap out of me). When I put the car in the garage on Sunday, it was running fine with a constant CEL (courtesy of code 49 and a Hitachi MAF). I probably won't get to drive it again until next weekend unless I convince a family member to go in and start it up to check if acts weird. It's very obvious though: the engine changes visibly and misses like hell.

It's weird that it just cleared up while I was driving on Sunday. I reset the ECU after that to clear the codes and after I reset the ECU it started to shook again and then when the car was at running temp, it went away (or it just randomly disappeared). After it went away again, I drove the hell out of it for a few minutes and it did nothing visibly but hang on to me driving it like an a-hole. It will be interesting to see if it starts up all weird again from a cold start.

you never checked the timing belt markd did you.....cause you sound like it is off the marks.

Bheinen74 wrote:you never checked the timing belt markd did you.....cause you sound like it is off the marks.

No because it comes and goes. It's not constant. I would think that an off tbelt would make it run like hell all the time.

Well, I got the car today...drove just fine. Still have a CEL and probably from code 49 - Improper Airflow Sensor. Is there any way for me to fake the JECS sensor signal?

Just make sure I'm understanding you. So you replaced your jecs with a hitachi and the car runs fine (minus the CEL) without changing wiring? Don't Hitachi's run one extra wire (I think it was a blue wire)? I haven't worked with them both so its interesting to me.

If I had an extra MAF of each variant I would pull them apart for ya and see what I could find out.

What would be involved in just going to a Hitachi ECU (I'm thinking that the only difference was the MAF and IAC and the IAC might even work with a Hitachi ECU - Have to check)? If its not an extreme pain to do maybe you could find someone to trade ECU's with...some nice guy that isn't using his old working 91 ECU. Let me know if you wanna take a crack at it.

turboleg wrote:Just make sure I'm understanding you. So you replaced your jecs with a hitachi and the car runs fine (minus the CEL) without changing wiring? Don't Hitachi's run one extra wire (I think it was a blue wire)? I haven't worked with them both so its interesting to me.

Yes, you're correct. Or, at least, I think so. The car runs fine and throws a CEL for code 49, which is improper airflow sensor. As far as I could tell, there was no extra wire.

I have one JECS sensor and a metal one, which I got from 555BCTurbo. He said it came off his 91 Turbo.

Right, the metal sensor is what I had on my 91.
I'm still not sure about the IAC however. If you were going to swap ECU I would suggest either asking around or checking a wiring diagram to make sure the wires from both MAFs go to the right places on the ECU (I think they proabably do - I haven't seen any issues posted). The only other thing you might have to play with is the manual/automatic trans selector on the new ECU. I have noticed a difference between different model years here. But all that amounts to is the grounding/cutting of a pin on the ECU. Let me know if you wanna try something. I'm not using my old ECU and its just gathering dust. Plus I have an extra Metal MAF if you ever needed it (I'd have to sell that to you though).


Just curious, did you try cleaning the plastic MAF? You have to be REALLY CAREFUL but it can be done. I use alcohol and a cotton swab. The car did seem to run better afterwords...just a thought.

turboleg wrote:Just curious, did you try cleaning the plastic MAF? You have to be REALLY CAREFUL but it can be done. I use alcohol and a cotton swab. The car did seem to run better afterwords...just a thought.

I never did try cleaning it, but I don't know how to clean it. I figured I'd just save myself and not try to clean it to make sure I didn't break it further.

Cleaning it is pretty easy. I just lightly brushed off the junk that was on the two elements with the cotton swap. Not saying this will fix the problem...but its worth a shot. Pretty easy and quick job.

You can get rid of the code 49 by I believe grounding pin 3 of the MAF sensor plug.

I know it's been discussed before, so you may want to search and confirm this.

But isn't that to make the Jecs work with the Hitachi's ECU? Or would it work both ways?

I've slept since that conversation took place, so I don't recall the details. Your best bet is to search.

Ahh, you have a mind like mine...it's fallen into the deep haze.

Engineer by any chance?

Well, I "cleaned" the plastic JECS MAF. At least, I rubbed a cotton swab with rubbing alcohol over the sensor. I plugged it into the car and it drives just fine - even got rid of some of the hesitation I was having with the metal sensor. Also, the CEL is gone as well.

It seems that on the metal sensor, the 4th pin from the left is completely gone - I think that's the one that threw the CEL for code 49.

excelent!