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Joe

Severe power problem!! Please solve!

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I have a 1990 Reatta and I cannot seem to solve this problem. 

It starts up like a charm but runs really raggedy and shaky just idling. When i take it for a test run and floor it, it shifts really hard and gets little to NO power. The max is 45 mph.

My Reatta has been sitting for the last year or so, so i can imagine something sat wrong. I replaced the spark plugs, air filter, in-line gas filter, fuel pump strainer, dropped the gas tank and cleaned it because the gas was superrr old. I replaced the MAF a year and a half ago, as well as 02 sensor, and the fuel pump itself. Fuel pressure is good on the gauge, with the pump switched on, yet when I drive it, it seems that its not getting enough gas??

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Welcome to the forum!  What did the spark plugs look like when you changed them.  Any of them look like they were wet with gas or any of them abnormally dry looking? You should do the complete fuel pump testing as described in the How-to guides here on ROJ to be sure the fuel pump is working properly under stress.

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The spark plugs were  a very healthy chocolate brown, with no black or deformed plugs, neither dry or wet. I tested the fuel pressure, and it kicks up the correct psi on turn key but i haven't done any other stress tests on it since i just replaced it a year ago. Ill give it a try! Thanks!

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How was it running when you parked it? Since it wasn’t mentioned I would guess the check engine light isn’t on and there aren’t any codes stored? Were the listed parts replaced before or after it started to run poorly?

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Posted (edited)

It ran perfectly fine before parked it. Not a single problem, its only got 90000 on it so it doesn't have too much wear on it. And correct, there were no check engine lights or codes besides the battery being disconnected code. The air filter, fuel filter, cleaning gas tank, fuel pump strainer, and spark plugs I replaced just recently when it was running poorly. Everything else a year and a half ago.

Edited by Joe

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If fuel pressure checks out, the only thing left in the fueling is the injectors themselves. The simple thing is just to listen to them with a stethoscope, wooden dowel, wood handled screwdriver, etc to see if one or more is dead. Further tests would be to go into overrides and turn each injector on and off to see what effect it has on idle quality. May need to unplug the IAC to keep it from compensating for the power drops during the test.

 

I suspect it is an ignition problem. Is it possible varmints have nested in the wiring or maybe chewed on it or possibly vacuum lines?  Spark plug cables, coil pack and module condition? Plug wires routed correctly, especially the rear ones. I have caught myself reversing a couple of them and it pays to triple check.

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Could check the vacuum lines to the transmission shift module or the module itself, since it is shifting rough.

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Posted (edited)

So I just checked the complete fuel pump load test/pressure test again and everything checks out. As well as the injectors, I did the good'ol screwdriver-to-the-ear-check and they are all functioning. There are no signs of anything living in the car or tampering with the electrical lines. The spark plug cables i replaced with everything else a year and a half ago and they are in good condition. ignition control module i also replaced  with the coil, but I did a resistance check to be sure, and it is functioning. Also plug wires, i checked again, are in the correct order.

I might add that i have had this problem before but it was because the inline fuel filter was clogged. After I changed it everything worked fine! Although now that i have replaced all of the fuel filters and cleaned the gas tank, it is still running poorly. Would really old gas be the cause of that?

Edited by Joe

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The gas would have to be pretty bad to cause this and with the tank cleaning and filter, are you saying the gasoline is old?? 
 

The injector clicking is a good sign but of course it doesn’t guarantee they are functioning at 100%. Short of having them cleaned professionally, a can of Techron or similar can’t hurt and may help. 
 

Does disconnecting the MAF help the idle? Readings from the MAF, tps, ignition timing, inlet air temperature, knock counts, O2 cross counts, fuel integrator and block learn, may help track down what is going on. Essentially we need to see if something looks out of range, especially when it is acting up

 

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On 7/17/2020 at 7:09 PM, Joe said:

When i take it for a test run and floor it, it shifts really hard and gets little to NO power.

 

9 hours ago, rogold said:

Could check the vacuum lines to the transmission shift module or the module itself, since it is shifting rough.

I agree. How hard the transmission shifts is controlled by the modulator valve on the transmission. If you have a massive vacuum leak it could account for the poor running and the hard shifting.  I would check the vacuum lines and check the intake manifold for leaks.

Vacuum_lines-1.JPG\Vacuum_lines-2.JPG\Vacuum_lines-3.JPG

Vacuum_lines-4.JPG

 

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Thank you all for the help.

Yes the gasoline was a year old since it had been sitting there, and i suspected that at first, but I just put fuel injector cleaner in with the brand new gas and it still hasn't changed.

Disconnecting the MAF causes the engine to stall pretty quick, it is pretty new so i wouldn't suspect that anyway.

I am still trying to figure out how to access the readings from the CO2 sensor and each of the injectors, ect.  So ill get back to you on those results.

I did however, do an extensive inspection with all the vacuum lines and even sprayed some wd40 on a few places just to see if the engine would flare, but they seem to be in good condition. I did have to replace all three vacuum lines branching off of the vacuum check valve since they were old and cracking. But still no change to the hesitation on acceleration or shaky idle. Plugging each line did not change it either.

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Are you certain the spark plugs are on correctly and not crossed?

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Update: So when I enter EC override and switch off cylinders 2,4,6  there is no change to idle quality. still shaky and hesitation on acceleration. But when I turn off the others: 1,3,5 the engine runs extreamly bad. Is that maybe a computer error? That conveniently that every other injector is not working? or that the 3 are actually bad? Wouldnt 3 bad injectors cause it to die very easily?

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Well it certainly sounds like the three rear cylinders are where the problem lies. You at least got different results when you shut off fuel to individual cylinders. Being the rear screams wires crossed to me or perhaps being pinched under/behind the alternator. It would be rare to have three neighboring injectors plugged but of course it is possible. Just for giggles, try swapping the wires paired on each coil. It should not make any difference but if the misfire moves to the front cylinders, something very odd is going pn

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I just drove a severely power deprived Reatta about 32 miles to my cottage. I bring this up since it was hit or miss for it to start. It has pressure low enough that it will run with the return line from the regulator completely removed, so it must be well under 35psi, probably a lot. Once running it is smooth but must be very gentle on the throttle not to outrun the fueling and it will cruise just fine at 65mph if sneaked up on. Surged some and was worse by the time I arrived, but it sure ran like it had half the injectors turned off.

 

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You know Hal that could actually be a test of poor fuel pressure, just remove the return fuel line. 

 I was there when we tried starting the car. What ended up being done [My machinist friend Bob] was remove the rubber tube between the air cleaner to the butterfly and squirt starting fluid in it. It was enough even with the low fuel pressure to start the car and allow 2seater to get the car to his storage shed.

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