If the car idles like crap with the AMM connected and idles great with it unplugged then the AMM is bad.

 

It idles like crap with it unplugged...

 

When unplugged the ECU puts it into a limp home mode which it should idle fine. But won't rev worth of crap.

But if it idles crappy then it has to be something else.

 

Try a new air filter. That does wonders. Also, I have a 1987 740 Turbo. My "Check Engine" light comes on all the time. I ignore it as the engine runs fine-usually. If your engine runs fine for the most part, why spend all this time and effort on a "Check Engine" light?

Oh yeah, the light does go off after a while.

 

Mines not going off. Also it runs pretty rich which seems to be negatively effecting my MPG. But the main reason is I have a temporary tag on it now (because I need a smog certificate) that expires at the end of the month...

 

Have you checked the coolant temp sensor?

 

It was replaced Tech. Here's my guesses on what it could be or be contributing to the problem

Bad AMM
Possible bad injector(s)
Possible faulty coolant sensor
Possible faulty 02 sensor
Bad main fuel pump
Idle motor
Clogged catalytic converter
Possible faulty ECU (mechanic said it was vovlo reconditioned one)

Any easy to do tests on the above components would be greatly appreciated...

 

I think you tested most already didn't you?

 

Seems I'll need to go through them again more thoroughly. I'll line up an ohmmeter in the next day or so. You light a match near this thing your gonna have a face full of mooncrater...

 

Is the fuel pressure regulator new?

 

No and I should test it again. The mechanic put a valve in the line and it showed around 40 psi which he said was normal. However it dropped once he unplugged the main pump at the connector under the rear seat and continued to drop until the car died. He said the main pump was probably bad. But would that cause this problem? I've read that when the main pump is bad the car won't run or will run poorly when under around a half a tank but it runs the same right down to the bottom of the red zone on the gauge...

 

With the FPR about 40 is close but if you unhook the vacuum line to the FPR the pressure goes up not down.
Unplug the vacuum line and see if there is gas in there.

 

So a little update. Had to leave it alone and get some work done as this car has practically bankrupted me. I am now here at my place with the volvo specialist again. There is no gas inside the fuel regulator line. Voltage goes up when the vacuum line is unplugged. He has installed a reconditioned air meter, and removed my aftermarket 02 and installed a bosch 02. The voltage on the aftermarket 02 went up to nearly .1000 when warmed up. Even slightly higher. With the bosch it reads around .900 or so. According to him it should be down around .400 or so. It is still giving us 113, 213, and 232 codes. Light stayed off until it was reved up then it came back on. We also closed the valve on the bottom the airbox (it was fully open). At this point I am completely pissed off at this stupid thing and at my ropes end. I have had two temporary tags and cannot get another one so I have to park a perfectly good running car and junk it because of some stupid emmisions glitch? What a joke. I used to have a pretty good opinion of volvos in general but that has dwindled to nothing short of telling people to stay the fark away from them at all costs. Any ideas anyone? This has become a complete joke and i'm upwards of $1500 dollars on just trying to get this $500 hunk of crap to pass the fricken smog test. Help..please

*edit* Mechanic says he is completley baffled and this guy came highly recommended. He is now going to replace the TPS to see if it's bad (he just put this switch on (new) around 6 weeks ago). He says he doesn't know what else it could be...

 

For some reason the O2 still doesn't seem to be working right it should be sweeping not standing still.

Also have you ever tried swapping ECU? (Sorry forget)

Also I wonder if it is a wiring problem.

 

Replaced the TPS with an older one that should work and it didn't change anything. 113..213..and an intermittent 232 still existing...

Mechanic says it has to do with RPM's. At idle with the computer cleared it seems pretty good. As soon as the throttle is even slightly cracked the codes pop-up. Jeez..something has to be bad here. When a volvo specialist is walking around in circles scratching his head what's the odds that the regular home mechanic or even the corner general mechanic can service these things? Slim to none. I'd say if you live close to nasa..get one..otherwise run the other direction.

 

In the end I have a feeling it will be something simple that was just overlooked.

Has he tried a new ECU?

 

The ECU he installed when the engine wouldn't start had the thing start right up. He says he's replaced all of 2 ECU's in his mechanical career meaning they don't go bad that often. He's now looking at the secondary temp sensor that's tucked way under the intake. Any thoughts on that?

 

Possible I have seen that before.

 

Gonna try plugging in another ECU today or tomorrow. I'll report back..

 

So went to a guy that buys and sells bricks and he let us borrow aECU from a '92 non-turbo for a test. Lo and behold it stopped throwing codes. It seems it was a bad ECU all along. Could've saved alot of trouble had he just attempted to install another one but he swore this one was good. When I find another ECU I'll report back if it all straightens out and passes smog. Tech, can't thank you enough for your help and patience (mine had pretty much run out). Your an asset to this site...