Help, no power....

[Supra chick's dad]

Hey first post here but read a bunch. I put a used Jap motor in my daughter's 89 Turbo Supra as the previous owner han the original out of oil. It all went in real well, and starts right up and idles nicely. However when you touch the gas pedal the rpm drops to 500 rpm's and wants to die. If you let up it returns to a smooth 800rpm's. Cannot possibly get it to rev at all. Here is what I've checked. MAF, TPS, O2, MAP, all connections on the engine harness for bad connections and every pin and socket behind the glove box. Here is what I have noticed, exhaust feels a bit weak at the exhaust tip. I can hold it back without any change in rpm and it doesn't seem to build up a lot of pressure. Small electrical zap when I turn off the ignition and put my hand oth the rocker panel as I get out of the car. This pulse is almost everytime.
Any ideas would be appreciated.....

[88Tsupra]

when u say electrical zap..im asuming you can actually feel it have you check all your ground wire then..

[Supra chick's dad]

Yes, I have a ground cable fron the neg batt side to the block and the trans to the body and the firewall to the exhaust manifold. All factoy points. I am thinking it may mean something in the electrical system is shorting to ground, but how would you know what and where? I also tried un plugging each sensor while at idle and non of the above mentioned sensors (Except the 02 sensor) made any difference in the idle or ability to rev.

[supramacist]

Have ya check'd the codes Daddy-O ???

The codes will tell you exactlly what you need to do.
It sounds like the afm. But hell. It could be a few things.

[IHateHacks]

There is also a ground on the lower intake manifold. It's brown and white wires going to 1 ring terminal that bolts to the lower intake manifold.

Did you check the ignition timing? Whats it at?

[Supra chick's dad]

Yeah, checked but there were no codes. I pulled the connector off of the tps while it was running, that threw a code, so I know it's keeping a record. I am thinking the zap is possibly as simple as static electricity as I slide off the seat. I see the car is well grounded and it really shouldn't have electricity running through it at a noticable zap (slight as it is) capacity. I am going to swap out the fuel filter, as I have fuel pressure (38lbs) but might not have enough volume to get it off idle. Also will try pulling the exhaust loose at the ex. manifold to eliminate a blocked cat. Other than that I am at a loss right now. Maybe the ECU??? Where is the best place to get a new ECU anyone?

[Supra chick's dad]

Ok, timing I have not checked and compression or vacuum either. I will. Dang the thing runs so smooth at idle, like a new car should. Also starts right up, not like retarded or advanced timing, or low compression. And the cam sensor wasn't moved during the engine swap. Contacts inside have correct air gap. I took the hose off at the throttle body to eliminate any possible restrictions in the air supply, no difference. I am thinking it has to be either blocked exhaust since it has weak pressure at the tailpipe or low fuel volume or just a bad ECU. It ran fine before the previous owner ran it dry. Sat for 2 years then got a used (Under 50K) motor. I drained the fuel lines and tank and put in fresh fuel too. New spark plugs also.

[cre]

Okay, first off where in CO are you?

Second, test the TPS per the instructions detailed in the TSRM: http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=101



EDIT: Oh, and I've seen 7M's idle smooth as silk even with the timing off by 15?. Mine. It's part of the beauty of an inline 6.

[supradaddy0803]

Yeah hes right I would check your timing belt and make sure everything is peachy there then next make sure your ignition timing is dead on. My 86.5 ran like that when I bought it because the guy just did the timing belt and it did the same thing it was like a tooth off and thats all it took to drive me nuts for a while. Also besides just your fuel filter check the fuel pressure regulator if it isnt letting the pressure build up then you wont have enough fuel pressure to run at anything higher than idle.

[Supra chick's dad]

Hey, thanks guys, it's good to hear all the ideas. I did work on the Supra all weekend and came up with some new stuff. I think I found the culprit. First to answer your questions, I did replace the timing belt prior to the install but I've done many in the past. I was extremely careful setting it up right and with the 7M it's as easy as they get. The timing I checked and it was dead on at 10 btdc. I was however able to generate a code by continously trying to get the motor to rev. eventually it crapped out enough to throw a 31. Hanes (cringe) says air flow or ECU. Toyota code book says air flow. Though I had cleaned a grungy MAF already, I decided to go at it again. Upon sterilizing the crap out of the honeycomb, and reinstalling the rest of the assembly, the car revved like normal. I was so freaking stoked! But now it won't idle. Go figure. I guess it's alll good though as the normal symptom for a bad MAF is poor idle. Now that I have seen the changes directly related to the MAF, I am confident the problem lies somewhere within that little black box. 360.00 for a new one seems a bit ridiculous, but neccesary none the less. I need to call around then order one. Too bad there isn't a Supra's only parts store where a guy could get a break on the huge markup. I understand when it comes to aftermarket stuff, but these things can't cost much to make. All the engineering is covered in the cost of the car originally. Whatever, I am on my way and will report after swapping the MAF out with a new one.