Which Computer for this project??

[SIF]

I’m sure this subject has been covered many times but I believe I’m in a unique position and need some definitive guidance from the Gurus on this forum. I ’m attempting to install a ’97 4.0l ohv (engine no. 95MT6090AD, Heads: 97TM6015AA with U above exhaust manifold) into a 1988 TVR ‘S’. Now this is a little british sports car which originally had a 2.9 cologne fitted, so I am sure the transmission and cooling are all OK. I bought the engine from EBAY , it was new from Ford never been run but obviously didn’t come with any ancillaries though it does have injectors. The one area I need to sort out though is the PCM; the original is an old EEC-IV 86GB-12A650-AC which I guess is no good as it runs off 2 MAFs, I recently managed to get hold of an ECC-IV and engine loom from a ’93 ohv over here: F37F-12A650-AGA. I also have a Dastek Unichip piggyback computer which was mapped to my old 2.9. Will either of these PCMs work with the engine with the Unichip or do I need to match the engine exactly as I have heard that the EEC-IV is more forgiving and ‘tuneable’ than the EEC-V? If so which PCM is the right choice? I also need to know which sensors are essential to make the engine run; luckily I don’t need to worry too much about emissions as the laws here are not too strict with my age car ie I don’t have CATS etc. Your help really needed and appreciated as I can’t just nip out to the local wreckers to get different parts to try as these trucks are extremely rare here - everything has to be shipped from US!… I was very lucky when a guy off this forum (BReel) went out of his way to source and ship me a flywheel. Thanks Guys - Simon

 

[ExplorerDMB]

EEC-V is more "tuneable" - the EEC-IV computer systems hardly have any varibles to change. You may need to have the computer sent out to a shop that'll kind of "reburn" the information into it as to what you have and what you are going to run. Talk to 410Fortune as he made a wiring harness for his engine in his BII -- he may be able to help you out

-Drew

 

[SIF]

EEC-V is more "tuneable" - the EEC-IV computer systems hardly have any varibles to change. You may need to have the computer sent out to a shop that'll kind of "reburn" the information into it as to what you have and what you are going to run. Talk to 410Fortune as he made a wiring harness for his engine in his BII -- he may be able to help you out

-Drew

Thanks Drew I'll try to PM him. So would you say that I could run either a IV OR V with some degree of success... just that there was some speculation that an older mismatched computer; "It will burn the engine down in a few thousand miles," (ranger station)

 

[ExplorerDMB]

I didn't read it right - I thought you were talking about a first gen explorer. It'd be better to run a OBD-II computer with that motor.

-Drew

 

[SIF]

Can the OBD-II computer run without all the sensors... as I stated I won't have the standard exhust so the Oxygen sensors are out, as is the vehicle speed sensor, the brake on-off switch and any other transmission based sensors... This is starting to give me a headache!!

-Simon

 

[SIF]

After a bit more research looks like running the engine in a permanent 'open loop' without any o2 sensors is a distinct possibility. The VSS - worries me slightly as it's role seems to boil down to cutting the fuel supply under closed throttle deceleration, does this mean that without it the engine decleration will not be as efficient a brake as it should be. (having driven a car with a fault in this department it wasn't much fun)! OR will the PCM revert to a los situation for this particular sensor and supply a limited 'idle amount' of gas under closed throttle?

 

[ExplorerDMB]

Running an OBDII computer without 02 sensors will be burning gas and won't allow you to get the effeciency out of the engine like you should. You may want to look into a custom computer just for you. I am sure there is someone out there that makes computers for what you want to run.

-Drew

 

[SIF]

Cheers Drew, I hear what you're saying just that a custom job has got to cost $$$$s hasn't it!! I will try contacting Bamachips.

Does it matter where the O2 sensors are fitted in the exhaust in terms of operation and the heat needed - bearing in mind no CATs? If I could site them further down the exhaust I may be able to retro fit some but would they get hot enough to operate correctly...

 

[ExplorerDMB]

some OBDII 02 sensors have heaters in them. However, 02 sensors are there to monitor the oxygen in the exhaust and to see how much content is cleaned through the cat. If you are not running and cat and the 02s see no difference in oxygen content, it'll more than likely throw an efficiency code. Search on the web for companys that build computers. Talk to some drag strip guys as they usually need to fab up a computer to run effectively. I know a guy at my work runs his sons camaro on a computer that allows you to tap in with a laptop and change the parameters. You may need something similar.

-Drew

EDIT: most 02 sensors operate at around500-600 degrees F

 

[IAmTodd]

I would look into converting the motor back to OBD-I(EEC-IV). It will be much simpler. Shouldn't take too much either. You can still have all of the benifits of the updated motor, and ease of installation.

 

[SIF]

I would look into converting the motor back to OBD-I(EEC-IV). It will be much simpler. Shouldn't take too much either. You can still have all of the benifits of the updated motor, and ease of installation.

This was the route I originally thought of until I came across that terrifying statement that an early computer on the fastburn heads would cause meltdown after a few thousand miles . I'd rather not change any mechanicals so what would converting the engine back consist of? I also guess I would need a chip to alter the ECU characteristics to be compatible with the engine year.

Drew have found a way of fixing the O2 sensors, just need to fool the secondaries into thinking a CAT is installed and working... I believe simulators or plug anti-foulers are both ways to do this (It's OK we're not talking about anything illegal here as the car doesn't have to have CATs fitted by law here)

-Simon