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Engine will not exceed 3000 rpm under load.

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Old 10-25-09, 12:27 PM
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KS Engine will not exceed 3000 rpm under load.

I have a 87 Turbo that will not exceed 3000 rpm under load in first or second gear. Car starts fine, idles good, and can rev up to 8000 rpm ok. This started when I was out on the highway 15 miles from town and drove over the edge of the apron where they put the grooves in the asphalt to keep you awake. Within a mile the car started to lose power, down to 4000 rpm in 5th gear. I limped back to town in 4th than 3rd gear at 4000 rpm. Took the car for a spin around the block and could not get over 3000 rpm out of it in 1st or 2nd gear. If i punch the throttle at 3000 rpm I get lots of backfiring.
Berif history- Car has 87,000 miles with a rebuilt engine about 4000 miles ago, a rebuilt and slightly enlarged turbo with upgraded blow off valve, 550 primaries and 650 new injectors. Reteck7 computer.

I have looked at every vac hose and electrical connection I can find and can see nothing loose or split.
Could this be a fuel pump problem- lack of fuel?
Thanks, any suggestions are appreciated.

Terry
Old 10-26-09, 06:02 PM
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Check your fuel (Injector and pump), another thing you might want to look into is checking your spark plug and wires.

Also for rtek1.7 you need min of 720cc for secondaries injector otherwise its not going to work (I forgot what will the result be in you don't have 720cc for the secondaries).
Old 10-26-09, 07:24 PM
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My mistake, the secondary injectors are the 720cc. I ran some new grounds, and adjusted the TPS, check the plug wires- they are almost new, than did a test run. No change. I can rev it up to 7000 rpm, runs rough as it reves up, but if i give it a lot of gas fast it wants to backfire and stall. Still will not drive under load over 3000 rpm, with a lot of backfiring if I give it to much throttle. Plan on opening up the gas tank to look at the prefilter and pump.
Old 10-26-09, 07:36 PM
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Test the TPS for dead spots in the range. Particularly towards the WOT range. You can also try unplugging it completely to see if there's any change. I'd also test the boost sensor per the FSM. ~3000 RPM under load is around where you should be going into positive pressure (boost), so it may be related.
Old 10-27-09, 02:50 PM
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The car must be warm when you unplug the TPS and try a go for a drive. If you unplug the tps while the engine is still cold and go for a drive you will not be able to go through the rpms. Its like a brick wall.
Old 10-28-09, 11:01 AM
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sounds like a tps problem
Old 10-29-09, 02:04 AM
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i found this pretty common, where your s pipe for the turbo inlet clamps to the front of the turbo they tend to split and just barely let air in(of course this is air after the maf not good) and when you try and boost underload it will start to try and suck in from that split
Old 02-06-10, 04:03 PM
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I know this is an old thread, but why not give it a little life. My '87 NA is hitting the same wall. It can hit higher RPM's in nutral, but stops gaining speed under load around 3500 RPM. I've re-gounded al of the engine compartment points and ECU. I need to re-check the adjustment on the TPS and I think the BAC is posibly bad (turning on the heater full fan drops the RPM w/o recovery) I'm trying to avoid pulling the injectors, but I have my fears. I'm trying a 2nd bottle of injector cleaner, I'm hopeing I can run it clean.
Two questions, 1. How harmful will it be for me to run the car 10 or 20 miles at 45 mph in third? In 2nd I can muster 30 mph at 3500 RPM, but I need to be able to drive it fast enough for the aux ports to open and the 2ndary injectors to turn on.
2. How do I verify the injectors are pushing gas???
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