My car is a volvo 1990 740gl non turbo. I seem to be losing power when it is hot out and the car is fully warmed up. It loses power at higher rpms and sort of bogs down, fights me to go further. This happens past 3k rpm usually. When it is night time/cooler out there seems to be no lack of power and it drives great. I have recently cleaned the throttle body thoroughly, replaced oil seperator, and flame trap. I am missing the two hoses that go from the throttle body to the vapor/charcoal box. Any input is appreciated!

 

Sounds like a crank position sensor to me.

 

I have already replaced the cps sensor. Weird after i posted this thread it stopped doing it.

 

At night time when the car drives so much better, thinking it could be due to the hot humid air here in Hawaii

 

CPS not a factor in your problems.
I'd look at the fuel pump, may be check the fuel pressure, assuming that the tune up items are OK, like plugs, wires, etc?

 

All of the tune up items have been replaced. I had thought the problem went away, but yesterday I went on a bit of a long drive and had an incident. The engine felt like it was taking in air kind of weird when I would rev it, almost like it was struggling to hard, and then the up shift light started flashing, the check engine light came on, and the car would barely drive. I ran the codes and I got 3-2-2 and the code for a bad mass air meter, or connection. I think 3-2-2 is hot wire. Does anyone know what this means? When I fiddled with it, it started driving again but the engine light did not go off. Is this likely a bad air mass meter or the plug and wire as well?

 

Is it a Bosch or Regina fuel system? That would make a difference with the codes. Also, with the fuel delivery. I am chasing a similar issue with Regina car right now and have it down to the fuel pump which I am about to replace.

 

It is a Bosch system. I think it would really have to be the AMM, the only thing I'm worried about is the plug and wire being bad. I haven't been able to locate a PN or anything for that. I wont rule out a fuel pump yet though.

 

Drive around with maf unplugged. Besides idle, if it runs better, swap in a good Bosch maf.

 

When I unplugged the maf the car just died.

 

You could be having and ignition misfire. I would make sure your cap and rotor are fresh BOSCH ones, and a set of BOUGICORD wires on there too. If you are totally cheap, you can 60-grit-sandpaper-tune-up your cap and rotor and get the crust off.

You could also be running lean. Check for airleaks by sticking a hose/pipe/tube in your ear and listen around for any leaks in the intake hose, intake manifold gasket, or idle air motor hoses. BAD MAF causes lean condition. DID YOU ACTUALLY GO DRIVE THE CAR and see if you have better high-rpm power???

Fix your hoses that go to the charcoal canister to throttle body. You say they are missing. That airleak shouldnt be big enough to cause the driveability issue, but FIX THEM!!!


Sounds to me like you are having a lean misfire. It will cause surging issues, poor mpg, and loss of power. Start with airleaks and drive WITHOUT MAF PLUGGED IN.

I had a similar issue a few weeks ago. Loss of high rpm power. Idle issues. Knocking on HARD accel, surging. It idled crappy with MAF unplugged, but DRIVING it had most of the power back. With the MAF unplugged your computer will default to a very rich fuel mixture. Even to the point where smoke can come out the tailpipe! However, car should run better too rich, than too lean. Too lean, you will have knocking and misfires. Too rich; you will be able to smell the raw fuel thru the tailpipe and will have lower power and some sputtering.

 

I have not been able to locate any air leaks, everything is tight. When I originally had this problem the up shift light was flashing, and when I got under the hood the plug to the AMM was loose. I tightened it up and the sputtering and up shift light went off, but the check engine light stayed on and the codes for 3-2-2, and 1-2-1 remain. I know the second was is for the sensor itself, but what does 3-2-2 mean? It says Air Mass Meter wire burn-off signal absent or faulty Wiring break between FI terminal 8 and AMM #4. I will definitely clean up the cap and rotor until I have time to order some parts from eeuroparts, but I think you could be right about running to lean the entire time I've been driving with the lack of power. I think maybe the sensor has been bad the whole time I've had the car. Is it possible for it to be kind of bad or is it a works or doesn't work kind of thing. When I first got the car it ran a code for this but after I fixed he PCV issue and plugged the battery back in the code was gone.

 

Also I am unable to drive without the MAF plugged in, it sputters and fights me hard, and will not idle very well

 

It can partially fail. Check your preheat flap in airbox too. Can fail and route constant hot air to maf and kill it slowly.

 

I see. I will definitely check the flap and see if that's what's happening. Seems a lot of people on these forums blow through mafs and this would explain it. Did you have any idea what that code I described might mean? I looked at my plug and it looks like one of the silver notches is missing. Is this normal?

 

Ha I made that same "discovery" about maf plug about 15 years ago. Short answer is: that's normal. I think it is only LH2.2 that uses all the pins. Lh2.4 has one pin "missing" on the plug from the factory.


Take all codes with grain of salt. They usually point you to the area of fault, but not the actual fault. Basically, erase them and do better tests.

I suggest the lh 2.4 tests in the link I always post. Find it. It will at least tell you if your maf plug is making good connection and circuit is complete all the way to ecu.

If it were MY car, I would throw a $50 used Bosch maf at it. I can get em all day long.


EDIT-Ok here is the link that really needs to be stickied at top of page! DO YOUR READING AND YOUR TESTS!!! in your case, especially the MAF wire tests at ECU plug. It wont tell you if your maf is bad, but if your connection is bad, your voltage and resistance tests at the ECU plug will tell you so.

Don't be lazy or stubborn! Do your tests!

http://www.volvowiringdiagrams.com/v...20Complete.pdf

Edit, Edit- The above test will make sure all the crucial wires to run the engine are in good condition. If you CAREFULLY, read the manual, it reminds you to check the grounds at the fuel rail and even to check their connection to the ECU. VERY important and a common point of failure. Also tug on the injector wires and slide the heatshrink back as well as you can and check that the wires haven't degraded inside the bundle. Probably NOT your issue, but on pre 1988 cars, very common.

 

Interesting that arrow flashed. Its based on load signal from ecu. Which is calculated from maf!

Blinking suggests it COULD BE a bad connection. Could have been flaky maf connection.

1990 had bad ecus too. Always a possibility. Especially if yours is pink label still. I havent heard of shift light flashing issues, but it can't be that uncommon. I don't know if thats a signal that the ECU is flaking out or not, but intermittent connections at maf seem more likely. You live in a humid environment, so I would pull back the boot on the MAF plug too and take a good look for any signs of corrosion. Maybe clean up the maf pins well and use dialectric grease on the connectors. I personally dont use the stuff, but have heard of it being suggested. I have pulled back many ECU, Ignition computer, and MAF plugs that somebody has greased up in the past. It probably can't hurt. Especially in a moist environment to prevent water intrusion.

Codes won't clear on their own. Disconnect bat for a little to reset ecu and also clear codes.

 

Thanks so much for he help Revolv! I unplugged the battery to reset the codes, and none of them came back, you were right with the faulty connection the plug was simply loose, but i do not know that that means my maf sensor is working top notch neccesarily. Where can you find bosch AMM sensors for 50 bucks?? The car always does seem to run better when its cool out i suppose thats just the way the car is for now.

 

I get em from local junkyards. In southern california there are junkyards PACKED with these cars.

I am still not totally convinced your MAF plug was loose. They clip in pretty well, but I guess it's possible....especially since you saw a blinking upshift light.

EFI cars shouldnt run any different cold than hot. Something is still wrong. You should fix it. Running too lean or rich can damage your o2 sensor or your cat. You also probably wont pass emissions if you live in an emissions testing area.

My 1990 240 has almost 400k on it and it runs perfectly. You just have to do your maintenance and know what you are doing.

I haven't heard you mention anything about doing resistance tests at the ECU. I plopped the link in your lap. I suggest, again, that you pull off the sheath at the ECU and specifically do your GROUND wire tests, MAF wire tests, AND your coolant temp sensor resistance tests. DONT BE LAZY OR STUBBORN! and of course dont take anything I say the wrong way. just tryin to nudge people to get out the multimeter and off the keyboard!

 

you are right i think something is definitely still wrong. The plug was literally halfway out when i went to go look at it, i should have seen it right off the bat. The car just feels like it struggles more when its hot out and the engine fan is working super hard. It sounds like a UPS truck lol. I wish i was out in Southern California with all of those glorious junkyards and minimal corrosion.