M119 woes - 1992 400E cuts out

[vanondemand]

Hi. I figured I would try here as I have searched and searched with nobody having my specific problem. 1992 400e has a high 1100 rpm idle, smells rich (but only sometimes) and at 125 kph, the power cuts out and it bucks with power cutting in and out with no more acceleration.

So far i have replaced: both fuel pumps, fuel filter, fuel regulator, replaced maf, checked fuses, checked for vacuum leaks, checked harness (looks new) checked throttle levers at back of engine and honestly, i’m stumped.

I doubt distributor and wires would cause this would it? Or maybe the up draft o2 sensor? The only thing i can think maybe would be the cats are clogged. But the car starts perfect no matter hot or cold, accelerates at wot (till 125 kph) and idles smoothly when shifted into d or r under load or at idle. Ac works great, everything works. Im stumped.

 

[emerydc8]

Have you pulled the codes for each module on the 38-pin connector? Clear them all and see which ones return. That might point you in the right direction. I would definitely take a look at the caps and rotors if they haven't been removed. What happens when you keep it in first or second gear and accelerate to redline? Does it cut out at high RPM? The car can appear to start and run smoothly with clogged cats until you reach a critical RPM, then it starts to pop and backfire. Mine was around 4000 RPM. BTW, don't do too many of these tests or you could damage the head gasket.

Ten years ago I made a post comparing the manifold pressure characteristics of a normal E420 and one with clogged cats. What I found was that the manifold pressure on the car with clogged cats behaved differently:

Catalytic Converter Replacement | M119 Engine

Having discovered that my catalytic converters were collapsed, I found these stainless 100 CPSI high-flow replacement converters on ebay and had them welded in last week for $100 labor. http://www.ebay.com/itm/310300540750?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 They are MBS 2 1/4"...

www.500eboard.co

To hook the vacuum gauge to a vacuum source, I tapped into the hose going to the three yellow vacuum pods near the brake booster, taped the gauge onto the bottom of the windshield where I could see it while driving, closed the hood and drove it around. You can crack a windshield here if you're not careful when closing the hood (ask me how I know).

 

[gsxr]

Ditto everything emerydc8 stated above. Check all fault codes, clear, see which return after clearing.

High idle RPM indicates the throttle actuator (ETA) system isn't working, likely a failed/failing ETA.

The power cutout and rich mixture is a separate issue. If there is no misfire at all (always smooth) it's unlikely to be secondary ignition (caps / rotors / wires / plugs). Does it cut out at a specific RPM, or will it pull cleanly to 6000rpm redline some of the time?

Also, does your car have optional ASR or not?

 

[vanondemand]

Okay thanks guys. Would there be codes even if there is no check engine light? Come to think of it, im not sure if i saw a cel illuminate on start up. Will advise.

 

[vanondemand]

Have you pulled the codes for each module on the 38-pin connector? Clear them all and see which ones return. That might point you in the right direction. I would definitely take a look at the caps and rotors if they haven't been removed. What happens when you keep it in first or second gear and accelerate to redline? Does it cut out at high RPM? The car can appear to start and run smoothly with clogged cats until you reach a critical RPM, then it starts to pop and backfire. Mine was around 4000 RPM. BTW, don't do too many of these tests or you could damage the head gasket.

Ten years ago I made a post comparing the manifold pressure characteristics of a normal E420 and one with clogged cats. What I found was that the manifold pressure on the car with clogged cats behaved differently:

Catalytic Converter Replacement | M119 Engine

Having discovered that my catalytic converters were collapsed, I found these stainless 100 CPSI high-flow replacement converters on ebay and had them welded in last week for $100 labor. http://www.ebay.com/itm/310300540750?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 They are MBS 2 1/4"...

www.500eboard.co

To hook the vacuum gauge to a vacuum source, I tapped into the hose going to the three yellow vacuum pods near the brake booster, taped the gauge onto the bottom of the windshield where I could see it while driving, closed the hood and drove it around. You can crack a windshield here if you're not careful when closing the hood (ask me how I know).

In first accelerates to redline and shifts perfect. When i first got the car and the lh module was acting up it would bounce off the rev limiter and not shift. Then i had it rebuilt by a member on here, and did all the above maintenance, and it shifts at redline 1-2 no more hitting the rev limiter/cutting out. Only at 125 kph.

 

[gsxr]

Okay thanks guys. Would there be codes even if there is no check engine light? Come to think of it, im not sure if i saw a cel illuminate on start up. Will advise.

YES. The CEL only illuminates if there are emissions-related faults. There are always codes on the other modules. Read the sticky threads at the top of the De-Coding subforum here:

De-Coding

Information pertaining to diagnostic codes, how to obtain and dechiper them, and how to remedy them.

www.500eboard.co

 

[Alphasud40]

I replaced the capacitors on this LH. If you want to send the unit back I will look over it again and test on my car. It’s always possible that failed capacitors might have caused additional damage.

 

[vanondemand]

I replaced the capacitors on this LH. If you want to send the unit back I will look over it again and test on my car. It’s always possible that failed capacitors might have caused additional damage.

I appreciate that. I will get codes read first and see if there are any stored.

 

[vanondemand]

Haven’t been able to scan it yet, but has someone deleted my check engine light, or do i just not have one lol. Im in Canada.

 

[Alphasud40]

You will have to make your own LED jumper to pull codes. Not the check engine light in the cluster.

 

[gsxr]

Haven’t been able to scan it yet, but has someone deleted my check engine light, or do i just not have one lol. Im in Canada.

Check above the passenger side headlight. If the emissions decal is Black, there is no CEL and no Diagnostic Module. If the decal is Yellow, there should be both a CEL and DM. Some 1992-1993 400E's do not have the CEL (and, some early production 1992 500E's also do not have it).

You will need a hand-held blink code reader to pull codes from the individual computers. Scroll up to post #6 above and click the link there.

 

[vanondemand]

Thanks guys!