artemyk

1987 4runner, rebuilt 22re

A little while ago I posted about a rough idle, fluttering sound and loss of power at low RPMs -- https://www.yotatech.com/forums/f116...uphill-301376/. Several suggested the fuel pump as a culprit. I only now got around to measuring the fuel pressure and it seems fairly normal: 38 psi with the jumpers set, 30-32 psi with the engine running, and 38 psi with the engine running and the vacuum unplugged from the pressure regulator.

At the same time I am getting weird possibly-TPS related codes. This is strange because when I first had this problem, I could successfully jumper T and E1 and the RPMs would drop, etc, suggesting the TPS was OK. Now when I jumper T and E1, I get the check engine light blinking 7 times then 11 times then 7 times then 11 times etc (sometimes only does the 7 blinks, sometimes also the 11). This is all TPS related, right? I did the tests suggested at http://www.4crawler.com/4x4/CheapTri...x.shtml#Table1, and things check out except that the E2-IDL appears to need adjustment (it goes to open/infinite as soon as I open a throttle even a tiny bit).

Could my original problem simply arise from a faulty TPS? If so, could I verify this by simply disconnecting the TPS and see if the loss of power issue goes away when driving?

yota tay

I heard without tps it would only run in either open or closed loop, so I don't think it would be 100% accurate. Adjust your valves if you haven't. I went thru the whole erratic idle/stalling for 7 months. I did tps, iacv, fuel pump/filter, egr, vacuum leaks etc. Ended up having the timing chain done and the same thing. Mechanic adjusted valves (mainly exhaust) and I've been good to go. Also take off boot to throttle and verify it isn't cracked. I highly doubt its the tps.

wallytoo

iTrader: (1)

you could attempt to get the tps into adjustment using mr. brown's linked page. that's what i'd do. if you cannot get the tps into adjustment, perhaps consider replacing it. but only after verifying that you cannot get it to spec.

ksti

Just because your RPM's drop when you jump TE1 & E1 doesn't mean your TPS is working properly.
I would check your timing also as it can relate to a TPS out of adjustment.
Do what "walleytoo" suggests.

artemyk

Thanks for all the responses, everyone. I am now pretty sure the root issue is not the TPS. I unplugged the TPS completely and the truck ran fine once, then the fluttering / loss of power issue returned. So its probably something else.

My next diagnostics steps:
- Check for any cracks in the air snorkel / throttle body boot
- Reset TPS code and adjust timing
- Recheck fuel pump
- Adjust valve clearances, per above suggestion
- Check for spark / inspect plugs
- Check mass air flow sensor
- Get vacuum gauge and check vacuum

Is there anything else I missed that I should check? Maybe the EGR system? IAVC?

Personally I'm starting to suspect the injectors, which is a pain...

Punchy

Signs I always run into with a bad TPS ((No codes) 4 times now)
really low acceleration, In auto its dawg slow and at least with a stick you can clutch more, The engine runs off the AFM.
Dead spots along with jerking.
It would run in closed loop most of the time but under real stress it might drop into open loop.
All this is extremely noticeable at high altitude.

Disconnecting the TPS just show other problems over what your already going through.

Suggest use linear ohm meter and slowly actuate the TPS and if you have fall off reading then its bad.
you can also test the AFM the same way.
Check EGR system again otherwise.

artemyk

As a follow-up, I believe I have traced this to a bad connection to the fuel injector on cylinder 1.