93' MTX acting up this morning. WTF?

[adidas_kn]

Okay soo on the way home from work last night after some WOT runs up to 110mph and then back down to 5th gear 80mph cruise my car threw a check engine light for about 5 seconds when slowing down for my exit. it still ran fine and the light went away. This morning I start the car up and it sounds wierd and is idling rough at about 1,100-1,200 rpm. I give it a couple slow part throttle revs and it kinda hesitates and the light would dim(UDP's) then it would rev. I let it warm up for about 3-4 mins and then proceed to drive to work and it doesn't feel right. I was in third gear and let off the gas to enter the freeway onramp and it kinda popped outta the engine bay like a small intake pressure pop. I merge carefully and accelerate at a moderate pace and it's still feeling off but still makes good power. Only thing is it would kinda hold back under constant throttle and then go. By the time I got to base which is about 15mins away it was running perfect. Like brand new. WTF? The only not brand new parts on this engine are the DIS which was working perfectly and the ECU. I didn't put the heat sink paste on the DIS module because they don't have that over here that I can find. I don't have time to order some either. I'm shipping the car back to the US on Feb 6th. I'm going to check the codes after I get home in about 1 hr. We'll see what it registers.

Also The engine has a slight knocking sound like rod bearings starting to go bad but EVERYTHING is brand new except the main bearings. WTF? It only makes this sound under part throttle at mid Rpm's. It doesn't do it all the time but it is kinda worrying me. It runs like a ***** ape everywhere but since I've had 2 other engines go down to rod bearing failures I'm scared. I'm thinking the Pennzoil Sythetic SM rated oil is too thin for the new bearings or something. I did 250 break in mile on 10w-30 dyno oil then changed it for the new synthetic. Before you guys say anything,you should know that Pennzoil is the only oil sold here on base. If I go to buy it out in town it costs a staggering $17 per quart. I put the synthetic in there just to get it back to the USA but now I might drain that **** out and put some thicker regular dynosaur Pennzoil in it to get it back. I only have 150miles on the current oil and filter(FRAM X2).

Thoughts? The brand new rod bearings better not be going bad already. I installed them to spec on this 180k 1990 engine that ran perfect.

 

[randy'sho]

just a thought...when i bought my 1st sho it was running exactly how you are describing.....come to find out i had two plug wires cracked on the plastic where it goes into the plug well! just a thought good luck though!~

 

[St Louis SHO]

I'd limp her until it gets stateside...

 

[adidas_kn]

K, soo I ran the codes and here is what I got.

511-No power to PCM pin 1 or bad PCM(Processor)

551-Problem in intake manifold runner control(IMRC)solenoid/circuit-solenoids

167-No throttle position sensor change in goose test

225-Knock sensor not tested(ignore if not pinging)

538-System did not recieve goose test

411-Idle speed system not controlling idle propperly(generally too high idle)


I'm kinda worried about code 511. My Cadillac kinda did the same thing with running perfect then running like crap. It turned out to be a bad ECU(PCM). Now it runs like an animal. Haven't really heard of SHO ECU's going bad soo maybe it's a bad ground or intermittent wire in the connector. I will pull my SCT chip and see what it does. What is pin 1 anyways? The thing with codes 538 and 167 are probably cause I blip the throttle a 1/4 or 1/2 and it basically hits redline cause of the Fidanza flywheel. Didn't want to **** my neighbors with the revving soo I cut it out. the 411 code is probably cause of my modified throttle body and IAC with deleted heated spacer.

 

[adidas_kn]

Oh and Randy, Everything is brand new but what I described in my initial post. It has 8.2mm Taylor wires, new Autolite plugs along with an Accel super coil.

 

[Storm-Chaser]

I seem to recall a number of people having issues with the SHO Accel coils, but never kept-up on it.

Also, was the timing belt tensioner new? If it was used, or new and wasn't properly tensioned, you could be hearing tensioner noise versus rod bearings, and insufficient tension or a bad tensioner could have allowed the belt to jump a tooth, especially since you were hammering it at the time.

 

[adidas_kn]

Accel problems huh? Maybe. The tensioner and blet and everything else are new. Maybe it's just due to the ultra thing oil. I just don't know how the bearing could possibly already be bad. I don't think they are but as soon as I heard the noise It immediatly popped in my head. The car randomly goes back to running perfectly. Onthe way homeit was oppposite. it ran perfect at first then kinda ****** under partial load or uppon trying to slowly accelerate in higher gears without down shifting. It would kinda fell like it was lugging.

 

[adidas_kn]

Wow! Nobody can help a brotha out? Even with these codes I listed?
What is Pin 1 used for? is that the main power pin or something? Could it be a bad groun somewhere?

 

[thecrew2999]

bad ground or loose wire... sounds a lot like the problem i had... keep checking the codes if they keep coming up different my money is on loose or bad ground.. my crossover tube was just loose enough it acted like crap at wot but anything before and nothing.

also if not avail replace the pcm.. got a spare one if you really need it

 

[ManySHOs]

Check your cats. I have a feeling that one is broken up after the WOT runs. It would explain why the car feels odd and is idling strangely. It might be rattling around at startup. Tap the cats and surrounding pipe with a hammer and listen for rattles.


Ian