I recently converted my truck back to speed density from a mass air conversion{to many tunability problems}. After I finished the job I went to start it and it won't start.Cranks over but, won't start.I checked all the connections and everything looks good.Well I call it a night because it's getting late.I go out the following day {which was yesterday} and I got the truck to start.It ran really rough and would stall out unless I kept my foot on the gas.After a few minutes of giving it gas it seemed to smooth out.So I took it for spin around the block and it stalled twice.On the last stall I couldn't get it restarted. Had to push it about half a block back to the house. Now I had the mass air conversion on the truck for about 2 years.My stock computer set in the garage in a box during this time period.When I reconverted back to SD I reused my old computer,which by the way has a superchip in it.Now my question is could the computer or the chip have gone bad setting up like that or could the map sensor go bad not being connected to vacuum for that long of a period?I checked for fuel pressure and with KOEO I had like 40 PSI. Where do I need to start looking.Oh by the way I checked TPS voltage before the reconversion and it was at a rock solid .96 volts. Any help or guidance would be appreciated.

Thanks ,
Cleve

 

bump

 

This is in regards to the above mentioned post.The truck is a'93 F-150 4X4 with e4od tranny and a 302.Thanks any help wpold be greatly appreciated.

Cleve

 

Come on guys nothing on this?

 

You can check the MAP sensor with a multimeter and a vacuum gauge per Haynes directions to try to rule that out. It would seem very possible for the computer to go bad from sitting in the garage. But I would recheck all connections again for good continuity. The two key things I would check above all else, would be the IAC and the ignition control module. No you're not having the typical problems associated with these going bad, but you've also done a reconversion that isn't typical either. Check those according to Haynes.

Couple questions for you though:
What do you mean by "too many tunability problems", which caused you to go BACK to SD? And where'd you get the MAF kit for your truck with the E4OD tranny? The one MAF kit that FMS makes is only for the AOD tranny.

Luke

 

The tunability problems I was having was mainly with the tranny.I adjusted the TPS voltage to .96 but the tranny just never seemed to shift like it should.Hard shifts,searching, torque convertor seeming to lock up or unlock at the wrong times and every once in a while the tranny would just shift to neutral momentarily. It just seemed that no matter what adjustments I made I couldn't get it right.I got the kit from a place in Georgia called Interactive Systems and Technologies. They supplied a Baumannator Tranny control module with the conversion kit.The kit was pretty pricey at 1200.00
I think I'm gonna remove the superchip from the old computor and see if that makes a difference and duoble check all my wiring. We'll see whats happens.Thanks for the reply to my post.

Later,
Cleve

 

Just keeping it fresh

 

Well guys I pulled some codes from the computer and it seems that every sensor on the truck is messed up or not reading right parameters.Says TBS voltage too low, checked it and it was .96. The scan said the map sensor , IAC , VSS , were all bad or out of parameters. Funny thing is they were all working fine before I switched back from the mass air to speed density. Could it be the computer being bad from setting in the garage for 2 years?

 

I would't think it could go bad just sitting unless something might have gotten spilled on it.?How about the grounds? Kinda sounds like a bad ground problem.

 

Maybe corrosion inside it?
You did rewire for the SD injector order and firing order right?

I had my truck sit for a few years when it broke down. When I started working on it again recently it did exactly as you describe. Started only with feathering the gas, only way to keep it running, would not idle.

I replaced the MAP and the O2 and she started right up.

 

Yep , I matched all the wires back up and plugged the original fuel injectors back in. I don't think anything got spilled on the computer either but who knows , it was in the garage in a box.

 

I think it's your MAP. When I replaced it, it started right up and idled. It was a bit rough but I no longer had to keep my foot in it. Pulled the O2, it had become so fouled from running bad that I replaced it. After that it idled fine.

 

Okay I replaced the MAP sensor and the truck still wouldn't start. So I did another scan and pulled these codes and this is what I got .

No.1 code 122 TPS signal voltage too low. I checked this before I converted back to SD and it was .96 volts . Plus the part is fairly new.

No.2 code 126 MAP signal values higher or lower than expected. Just replaced the MAP today.

No.3 code 327 EGR valve position sensor voltage too low. I haven't replaced this sensor yet.


Now what do you guys think.The first two sensors are new and the computer says they are bad along with the third.Think it could be the computer?

 

O.K. I'm problablly going to mess this up but I'll give it a shot. These 3 sensors share a common VREF wire going back to the ECM. Looks like to pin 26. I believe this is where to look since these 3 share it but nothing else does.

 

I'll check it to see if that's the culprit.Thanks