ECM Issue on a 3.4 manual with topend swap

[black34v6]

so i finally had the rest of the 3400 stuff put on. i now have Gen III Aluminum heads from a 2000+ Grand Am instead of ones from a 1996 Grand Am (change in intake port size to 1.76" valve and 1.6 ratio roller fulcrum rocker arms)

i had the 2000+ 3400 intake manifold put on as well (larger runners) -- and now i ahve another problem.

the car cuts out occasionally. i am thinking maybe its knock detected by the computer from the larger ratio rocker arms, or something else, but im not sure. i had the car taken to a mechanic who scanned the ecm and told me that he got a code for every engine control sensor, + a 51/99

51 : error communicating with the PROM/EEPROM
99 : bad EEPROM Program

so something tells me my comp is fried, or #2 - i overmodified the car for the stock program.

now the car runs pretty decently..sounds a little like its missing a cylinder, but..it runs decently..the problem really is that it cuts out intermittently. ill be driving along and she'll stumble, then just straight out die in the middle of the tach..and ill pop the clutch and she'll come right back on and drive for a while longer.

or she'll cut out altogether and i have to wait a few mins and then its fine. should i replace the main wiring harness maybe? (could be a wire getting heated and coming apart..)

im fishing for answers cause im out of them...

thanks.

-R

[StudlyCamaro]

if you had a 93 i would send you a spare computer, but it shouldnt work on a 95.. whatever it is i hope you get it figured out

[Wicked 3800 V6]

Fuel pump / fueling issues? Happened to us in our vette ... [img]smile.gif[/img]

[TealV6]

Do you have MAF in the new setup?

Could have talked about this on the phone... but you know... had to catch up on the dirt ;)

[ February 11, 2004: Message edited by: TealV6 ]</p>

[black34v6]

lol.

teal dude - its a 3.4L v6. no MAFs.

as for fuel issues...my dad said its a fuel problem, ive had numerous ppl tell me that its the ECM..

dunno myself, thats why im askin.

[TealV6]

Well.. sounds like it's time for DFI Gen IIV :D

Don't mock an admin... it's not healthy for you [img]graemlins/stickpoke.gif[/img]

[black34v6]

nice nice..

ok so...no one else has an answer to this?

as for the DFI..id love to. you gonna buy it for me?

[StudlyCamaro]

come on buddy , a FAST engine management system isnt much over a grand.. same with the motec and haltec's [img]graemlins/rofl.gif[/img]

[viper98885]

I don't think that you've overmodified the engine for the stock computer. You know what I have done on mine (I think my cam is a little more radical) and the engine runs fine on the stock computer.

It does sound like the computer is a little screwey. I would not point at the fuel system though. It just doesn't sound like that would be the problem.

[MustangEater8251]

I asked a freind he said he might have a spare 94 manual computer... thats why I said maybe last night...

as for his thoguhts, TPS? MAP sensor?

[black34v6]

didnt think bout the TPS. i have replaced the MAP sensor on the reccomendation of one mechanic that looked at the car, didnt help. i totally didnt think of the TPS tho..i might have to investigate that...

why would a MAP / TPS create an error 51 or 99 tho?

[gen4]

This may seem alittle of track but when doing my 83 S10 Blazer 4x4 2.8 to 94 Fbody 3.4 swap,I tried both computers(auto and stick)Both worked OK after a run in period of a few minutes(autolearn).
The manual trans ECM didnt seem to run as good as the auto trans one,even though Im running a T-5 trans.The Auto trans ECM puts out a code for transmission because its missng those components but it didnt hamper driveability.
Im thinking that all of your grounds need to be cleaned and checked.
Ive seen alot of good mechanics ignore the grounds and spend many hours chasing their tails due to this.If you was closer to Central Fla I would help.

[viper98885]

<blockquote>quote:</font><hr>Originally posted by Russell:
didnt think bout the TPS. i have replaced the MAP sensor on the reccomendation of one mechanic that looked at the car, didnt help. i totally didnt think of the TPS tho..i might have to investigate that...

why would a MAP / TPS create an error 51 or 99 tho?<hr></blockquote>

You can test the TPS very easily with a multimeter. You should do that before you replace it. I don't think that it will be your problem though. Furthermore, I don't think it would throw a 51 or 99 code.

[black34v6]

interestingly enough...i hooked my auto x-ray up to the car and ran the trouble codes...i only got 4.

3 were from the egr not being connected.. and one was "Torque Converter Clutch Error" (i have a manual?)

anyway...thats my update.

[Tiago]

A tps can check out ok with a multimeter but at part thortlte it may give out erratic signals which will **** with stuff anwyay so sometimes its just good ol trouble shooting....