John Boy

iTrader: (3)

I've been making some slow head way with my TPI swap in a CJ7 jeep, or so I thought. This is a 350 with ARAP bin, with AUJL timing table. I set the injector constant to 24lb. and I lowered all the values in MAF table 1 by multipling the entire table by .8. This idles and runs much better, not perfect by any means.

Yesterday I took it for a drive locked in open loop. It was running fairly well for about 30 min, then horrible. I left without my laptop so no log. I had to put it in neutral and restart several times, also keeping my foot on the gas at stop signs just to get home. When I get home I can't connect with tuner pro until after I unhooked the ecm for a few minutes. Then I could connect and it crunk and ran fine for 5-10 minutes. Which is when I quit messing with it for the day.

Today I left the house with laptop and drove around for about 45 minutes. Still locked in open loop. Same bin as the other day. Again it was running pretty good. So I recorded a log on the way home to look at later. Titled openloop1 attached below.

Now when I get back in my garage, pondering what happened yesterday, it happened again.

It's hard to explain but the whole vehicle just changes. It goes from pretty good to horrible, the smell of gas is overtaking, missing, spitting, sputtering, and finally dies, and is very hard to crank. And when I does hit I have to keep pumping the gas pedal to keep it alive.

Now when this happened I broke the laptop back out and was able to connect this time. No codes. I was able to get a short log recorded. Titled openloop2 also attached below. The IAC was at 160 and the injector PW was much higher. That's all I see right off the bat. I could only keep it running for a minute. After that it wouldn't crank at all. Battery voltage seemed a little low so I put the charger on it and took a break. After about 20 minutes. I fired off again. Running poorly again, but running on it's own.

Can an ECM overheat? It seemed to do better after a cool down period, and it was pretty hot to the touch.

If someone wouldn't mind taking a look at the logs and perhaps help me find any difference in the two that might point to the cause of this frustrating problem I would be so grateful. Thanks.

RBob

iTrader: (1)

The ECMs do run hot. Although it sounds to me that the ECM is bad. Pull the cover off of it and start the engine cold. Now press on the ECMs PC board. See if the problem comes and goes while doing this.

RBob.

John Boy

iTrader: (3)

Will do. It'll be about 2 weeks before I have another chance to mess with it, but I'll post back then. Thanks.

John Boy

iTrader: (3)

Welp, I went ahead and got another good used ECM. I am so disappointed, because that is not the problem. Had the new ECM in and running pretty good and after about 45 minutes, same thing. Just stutters and dies. Just like before. I sat down to collect my thoughts for about ten minutes and tried it again. It ran good for about 3 minutes at this point then goes to crap again. It just seems like something is getting hot and cutting out, but what. The MAF is rebuilt, new delco ESC, new coil, new heated o2, TPS and IAC. The only thing I can think of that I may not have replaced was perhaps the CTS or MAT sensor.

BTW, I know this sounds crazy, but it seemed like the fuel pump got louder right before it went south. Like one minute I couldn't hear it, the next I could, then running like a turd. I dunno...

Does anyone have any ideas? I would hate to spend this much time and money on the TPI just to rip it off and go back carb, but I can't keep this up.

Thanks guys.

RBob

iTrader: (1)

OK, what did the fuel pressure do right before the engine cut out?

RBob.

John Boy

iTrader: (3)

Hmm, I have no idea. Over the weekend I will hook up my fuel pressure gauge and monitor it during one of it's fit's. That's a good idea, thanks.

John Boy

iTrader: (3)

Fuel pump is bad. It took close to an hour today but it finally quit. I got louder for a couple of minutes then got very quiet, fuel pressure started falling and the engine struggled to keep running, then died.

I gave it a little while to cool off and it would come on again and build pressure but only for a few short minutes. Same thing again.

It's a Walbro that I bought new just for this swap, it has less than 12hrs run time. I just never thought about it being bad.

So thanks for steering me in the right direction.