no high rpm power

[paulc]

is it common for an 87 n/a to have little power or a slight power drop off when accellerating in 1st and 2nd? Is it an oxygen problem or is it due to being an n/a and fuel injectors being "maxed out" at hight rpms?

[gearhead290]

mine didn't do that. I likey kmopressors

[3sonfather]

Paul,
Can you be more specific? At what rpm does the power drop off? And does it do it consistently in all gears? Have you done a compression test lately and what are the values?
Scott

[XJOSHX]

Start with the cheap stuff. It's common for a fuel filter to kill top end power. My friends mustang cobra was having a power drop off at the higher rpm's and I changed his fuel filter and it fixed it. He did all kinds of work too. He changed the tps, injectors, re calibrated his maf, new plugs, wire cap and rotor. All along it was the fuel filter. Give us some more details so we can try to narrow the problem down.

[paulc]

1st and 2nd gear are really the ones i'm *****in' about....can't give any specific rpm readings since my tach has not worked since owning the car...bummer i know. I just had the timing belt/water pump service/upgrade and the car runs great except for the forementioned. I think the car has been like this since I bought it.....don't think it was from the recent service. I just put some Techron fuel system cleaner in with a new tank of gas....will see if the injectors are just dirty or if there is a bigger problem like compression.

[3sonfather]

do the compression test and report back - you may be spinning your wheels until you realize the true health of your engine.

[todwic]

Originally posted by 3sonfather
do the compression test and report back - you may be spinning your wheels until you realize the true health of your engine.

yup yup yup
What the hell are you looking at?
-Duckman

[Frank B]

I feel a head gasket coming on...

[ruechaos]

From what I'm reading, "no high rpm power" in 1st and 2ed gear seems right on a 944 NA. There simply isn't enough breathing in an 8 valve car. 1st gear is simply to get you going, 2ed should pull like a mother f*cker, but only to a point. How many of us acutally go beound 4 - 5k rmps in either of those gears? I sure don't. I personally dig 3rd and 4th. Plenty of power for street and highway use with enough passing power in reserve.

-Tony

[paulc]

i figure maybe that's the way it should be...nonetheless i am going to do a compression test in the next couple of days.

A) do i just unplug the starter coil plug and hook up the guage to the #1 spark plug to do the test on #1?...ditto for 2,3 and 4?

B) is there more to it? how long do i "crank" the engine?\

C) when i stop cranking and watch the guage will this show me any leaks?

[todwic]

firstly take out your sparkplugs, the tester goes in the holes, and the rest of the plugs out makes it easier on the engine/starter to turn. I think the best way to crank it is to unplug the 9 pin connection at your brake booster, and run a jumper from you pos. side of the batt. to the female connection on the 9er pin. I believe it's the hole in the middle oposite of the curved part of the plug. that way you can crank your engine w/o worries of dohickying the coil and other nonesense. Make sure when you're done cranking that the live jumper isn't going willy nilly around your engine compartment. fires have started that way. I tape the end of my jumper when not in use.

[paulc]

todwic...thanks for the reply and instructions...what would happen if i just unplugged the coil wire?...i haven't done it but thought that would be easiest....also, you said to take out all the plugs for easier cranking...doesn't this effect compression? I thought they would all be done one at a time.

[Makis]

I think if you have compression problem then you will have also problems at low rpm. So my approach will be to check the following items:
1. Exhaust system is not blocked. CAT is not operating at its peak.
2. Fuel system. Fuel pump delivers enough fuel, fuel filter and fuel pressure regulator.
3. Ignition system, wiring, grounds, electrical connectors in engine compartment.
4. Mechanical problems with the valve train, like the camshaft or weak valve springs.

Other possible causes will almost certainly cause low rpm engine running problems. These are dirty injectors, burned valves, head gasket.

[paulc]

sorry about last reply...should have check the Haynes manual...got everything understood i think. will check in the near future. really not a big power loss, may be fairly natural as one of you replied being 1st and 2nd gear....3rd and 4th pull really strong...car idles fairly well.............damn tach...wish it was working......mechanic said the dme is getting the signal but it either is not processing it to the tach or that the tach is dead.....as Frank would say................"poop"

[Paul Glasson]

Just a question Todwic could probably answer. I was advised by a garage that when cranking an engine to do the compression test it is best to pull the HT lead out of the distributor and ground it to prevent any damage to the DME. I am sure the advice about the 9 plug connector is the way to go but won't grounding HT be ok? Not a solid ground, a 2-3 mm air gap should be left otherwise coil will get nackered.

[todwic]

I don't really know about the ground, sorry. That's why a skip the whole mess.

[Roger Hall]

On my 81 924 it is recomended to ground the coil. It may not cause any damage but its too simple a precaution to ignore.

[todwic]

Originally posted by FR Wilk
For those of you who will be grounding their coils this weekend, I have good used late 944 DMEs at $300 each. I take PayPal and can next day air it anywhere in the US. Humor, arrrr, arrr.


FR Wilk
http://frwilk.com/944dme
http://frwilk.com/early944
email: motronic@frwilk.com
________________________________________________
_

LMAO!!

[Roger Hall]

Thou shalt not question FR

[Paul Glasson]

Roger-Was the coil grounding you read about on the LT side or the HT side?