waltrobak

I have the 4.6L motor from an 01 GT installed into an 87 Jeep Wrangler. The entire project took two years and it has come out awesome. I have a custom wire harness from RJM that was design for the motor and application, the G1Z2 stock computer that came with the motor and a custom tune downloaded to it. The motor runs perfect, when I can get it to start. We are having a lot of trouble with it starting when it is cold, anything under 45-50 degrees. I have gone back and forth with datalogs and downloading new tunes, but we are no further along. Keep in mind that I live in upstate NY, we are averaging 10-20 degrees during the day and -10 at night.

The one thing that we came up with in the datalog is when the motor is stone cold and not running the short term fuel trim is showing a .69. From what I am being told is that means it is showing that it is running lean and is trying to dump 31% more fuel during start up. Both short term banks are reading the same numbers. Oh, also when the motor is running and you shut it off even for 30 seconds, it will not restart until you shut off the fuel pump. I have a temporary switch wired in so I can shut the pump off.

Does anyone have any ideas? I have been told by a few people that it does not sound like the computer is bad, but I have two brand new Ford OE O2 sensors, new IAT, new plugs, all new injectors, all new Accell COP's, and every other sensor on the motor is brand new as well. Is there anything that I am wising that could be throwing this off at start up?

We pined out the wire harness and that is all correct and like I said when it starts up and is running the motor runs great. The datalogs also show everything is perfect when the motor is running. I am at a loss at this point.

Thanks for the help.
Walt

Derf00

could be programming for the pats system is not correct. Pats is fords anti-theft system...

http://cars.blurtit.com/1386398/how-...i-theft-system

waltrobak

The custom tune has all the PATS removed.

Mike@DiabloSport

When it wont start, are you saying it cranks, but will not fire?

What are you flashing the PCM with?

First thing I would do...is grab a set of (known good) stock COPs and see if it helps

waltrobak

It will crank over with no problem, but it will not start. It will spit, pop and ocationally a sever back fire out of the tail pipe and some real strong raw gas smell, but not start. I had stock COP's in there that appeared to be working, but I replaced them all anyway. I had it running with the new COP's and it ran great, but I started it from a heated garage. As soon as I leave it outside it is done. I have a SCT 3000 hand held programmer and I have been working with someone since before Christmas and we did iron out a few bugs with his programs, but I am starting to think that he has hit a wall and is not sure what to do at this point. I have done about 10 data logs on the motor and when it is running the data log show that everything is perfect and it is. I did a data log the other day in the morning when it was very cold and I did it without the motor running, just the key on. It showed that all the sensors are were they are supposed to be at start up, but the only one that was off was the short term trim. It showed that the motor was about 40% lean and it was trying to compensate by dumping excess fuel on start up. I am just a novis with these programs and data logs, but that is what I am being told and I can believe it by what I see with the motor. I am not sure that he knows what to do to change it.

Mike@DiabloSport

stock injectors and MAF?

I wish you were using as different device, I'd be happy to take a look

waltrobak

Yes, I have stock 19lb injectors and I am using the stock air filter and air intake tube that came with the motor. I have a new MAF and IAT sensor in it. It has a K&N air filter on it that was cleaned and oiled, but I have gone back a couple of times and cleaned the IAT and MAF to make sure there is no oil on them. I called Diablo yesterday morning and spoke with Vas, he suggested that I get in contact with Brian @ Drag-on Tuning. I spoke with him late yesterday and emailed him all of the info for my project. I believe that he works for Diablo is that correct? Do you know much about him?

Mike@DiabloSport

Yeah, Brian would be the guy I want looking at this

waltrobak

Thanks for the help.