In searching the forums, it seems a fain amount of people have commented that the remanufactured amm's sold through FCP groton are junk.

my car has very erratic driveability problems. i have chased all sorts of problems, changed all sorts of parts, pressure regulator, relays, ignition coil, and i bought a reman. AMM.

the car right now, will sometimes accelerate fine up to 5k (its a 740 turbo 5 speed) sometimes, it will accelerate fine to 3k and then it just won't accelerate any further, sometimes, it will lurch when i try to keep it at a constant speed.

it never throws codes and the check engine light never comes on. when it initally did this i put in a used amm and it was fine for a few months and then it had some other problems that i thought were fuel pressure related. i think that may have been a problem and maybe the AMM failed?

i am also wondering if the harness that connects into the amm can go bad. the tabs in mine looks little loose.

thanks,

mike

could leaks in the intake season cause these problems?

i was looking at my hoses today and with the exception of the turbo to intercooler hose which seemed new, the hoses all seemed original and kind of crappy. i coudln't find any holes but seems you generally dont' see them.

I don't know how accessible the turbo AMM is, but a voltage check on connector pin 3 (third from the REAR) will give you some idea of it's health.

You'll have to peel the rubber "boot" back for access to the pins with the plug connected. Probing the Blue-Red wire pin with the Key On should show at least 1.2 volts. More is better–1.4, 1.5 etc.

If the front is open, you should see the voltage rise a little as you fan air in by hand.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Any correlation with poor running and low fuel level in the tank? If so could be a bad/cracked pickup tube. Are the plug wires Bouricord brand? If not replace them. It makes a big difference with turbo engines. When it won't go over 3000 rpm are you trying to get the turbo to spin and just not getting any boost?

the wires are the bougicord (sic) and the problem has no correlation to the fuel level.

as i said, i can drive down a street, gun it and it will go fine, and then get to the end of the street and try to do the same thinf and it will not run over 3000 rpms. the turbo seems to be working okay, and its not that it won't go sluggishly, it just won't go over 3000 rpms.

i am thinking its some sort of odd electrical issue or something.

the first time it did this i found my amm was filled with deteriorated air box foam and i put in an ebay AMM and it was great for a few months. then when this started again, i got a reman. from fcp groton and it has continued to do this.

i have since then, changed the RI relays, the fuel filter, the FPR.

my grounds seem to be okay, though i have two ground straps running from the cylindar head and can't see one form the intake manifold, however, it has always been like this and ran great fro the first 9 months.

i ahve suspected that the harness at the amm is bad as it seems to be missing a pin, but again, why would it work fine once and then not work the next time. also everytime i disconnect and then reconnect the harness it seems to work fine for a little bit.

also is it possible that a vacuum leak on the intake manifold gasket could cause such drastic drivabilty issues? or a bad fuel injector? i have one injector that i can rotate when installed, that can't be good.

I think if the AMM was bad you'd get a 322 code for that.

I would look at fuel delivery , at least to rule it out.

What year is this car? Can you spot any weather related patterns?

Greg

car is a 1991 740 turbo 5 speed with 140k.

weather does not seem to effect the problem.

it seems to be more electrical/sensor related then mechanical.

i called fcp and they said that they have not had a high failure rate on the AMM in question.

Does you car have the 'Hall Sensor' connections on the distributor or did the 91's move away from this?

i believe it does not have a hal sensor. there is no wire on the distributor cap.

If you do have one it is seen as a small plastic connector at the bottom of the cap where it seats on the distributor (down by the firewall). My '86 gave me all sorts of grief with sputtering, no starts and lack of high RPM's. These seem cause suspect signals to the ignition amplifier (by front fender) AND they also sit right below the weather sripping on the back of the hood and can get soaked if things aren't right.

Greg

You can always spray the AMM with the special aerosol AMM cleaner sold by NAPA, but I don't think thats the problem.

It "could" be a few things,
HT ignition breakdown at hi speed/loads (tune-up)
fuel delivery/pressure
or sensor electrical related.

i've changed the radio suprssion relays and replaced the FP regulator. the fuel pumps appear to be working okay from the sounds they make.

the ignition coil is new and the plugs, cap, rotor and wire all have less than 5 k on them.