engine dies under load - any suggestions?

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vvurdsmyth
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engine dies under load - any suggestions?

Postby vvurdsmyth » Mon Jun 02, 2014 8:43 pm

'86 M20- cold start- fine, but when warmed the engine dies when clutch is let out in gear; it idles rough but if it doesn't stall, can be sometimes be teased to reving in neutral; when the revs are high enough slipping the clutch can get it moving and keeping the revs high (running in the lower gears) it seems normal, stopping at a light I have to play with it again to get it moving; when idling often it will die or nearly die when the accelerator is pressed; often when I get it moving by slipping the clutch it will accelerate, then die.

It has a new AFM, new throttle position sensor, new temp sensors; new spark coil, ignition wires are fine; just checked the cold start valve hot, it's tight; the vacuum line to the fuel regulator is fine; there seems no diagnostic check list in Bently's..

.. any suggestions..?
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Re: engine dies under load - any suggestions?

Postby 87e30 » Mon Jun 02, 2014 11:15 pm

You check that the connector on the AFM is making good contact? Is the TPS installed at the wrong angle? Have you checked for vacuum leaks? Spray some brake cleaner around all the hoses, etc., and listen for any change in engine sound.
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Re: engine dies under load - any suggestions?

Postby vvurdsmyth » Mon Jun 02, 2014 11:58 pm

Thank you 87e30, most connections have been recently cleaned, including the AFM; most suggestions from other forums have centered around the fuel regulator, and that seems to fit the power at higher revs, which increases vacuum and fuel pressure; and that also is consistent with the ongoing problem of sputtering when it rains... low air pressure; was thinking whether it has an air pressure sensor, but Bavarian says this model doesn't have one; it seeming to be the best bet, ..going to order a new fuel pressure regulator tomorrow; will let you know how it turns out...
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Re: engine dies under load - any suggestions?

Postby 87e30 » Tue Jun 03, 2014 12:27 am

I didn't see you mention sputtering when it rains in your OP. Mine ran like total crap every time it rained because my dizzy cap was broken in 2 places.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: engine dies under load - any suggestions?

Postby vvurdsmyth » Tue Jun 03, 2014 12:41 am

Thank you 87e30, the sputtering in the rain was another, previous post, and yes a cracked dizzy would do it; but while I said "when it rains", there have been times when it was just threatening to rain and it happened leading to the theory of an air pressure sensor, or something sensitive to humidity, and as long as you mentioned it, I'll check the dizzy.. it could be the problem... high revs might somehow 'get by' a voltage leak due to a crack.. will check it out.
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Re: engine dies under load - any suggestions?

Postby M20_fever » Wed Jun 04, 2014 3:17 am

By new AFM do you mean new to you, or brand new? '87 should have the dual fuel pumps, have you checked that the in line pump is working properly? I suggest putting a vacuum gauge on it and seeing what its pulling at idle, and a compression test should be done as well.
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Re: engine dies under load - any suggestions?

Postby vvurdsmyth » Sun Jun 15, 2014 10:49 pm

87e30, new TPS, but will check to see if it might have slipped;
M20_fever, new AFM;
since no low end torque may be the timing belt, 'jumping time' (happened to my '47 Pontiac, eons ago), and it coming up on timing belt changing time, that is what I am doing now; gotta rule that out; will let y'all know how it turns out.

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