Throttle problem when at operating temp.

[ThreeD]

Throttle problem: When engine is cold, throttle response is normal, with good power etc., however, when engine reaches normal operating temperature, the engine is reduced to "1 hp" ("one human power" pushing it back into the garage). I have included the two gauges to supply more information: i have 3 ECUs, 2AFMs, 2 of all other major intake stuff (IAC, throttle bodies etc.), but these symptoms are constant across all of these parts. IAC pocvip'd.

Video when engine cold


http://s476.photobucket.com/albums/rr125/ThreeD_MR2/?action=view&current=MR2engtempcold.flv

Video when engine at normal operating temperature

http://s476.photobucket.com/albums/rr125/ThreeD_MR2/?action=view&current=MR2engtempnormal.flv

:confused: All suggestions gratefully accepted.

[Goldy]

Strange, the only time i've seen something like that is when the connector came off my AFM, i'm thinking if its working when cold but not when warm, poss something with the cold start injector or temp sensor?

[ThreeD]

yea a strange one - checked the temp sensor (good resistance numbers at all temp ranges). Tried to do a EGR vacuum test, but i can't get the engine to rev to 2500 when warm, to see results. Will do some electrical testing for the AFM tomorrow.
Was listening very closely when the engine gets into the trouble temp range and it sounded like a flap was closing "sound". Try again tomorrow

[snowtigger]

I'll have a bet on a dodgy afm or vacum pipes not correctly fitted, it's not sucking in air round the manifold is it?

[ThreeD]

Did an AFM check and all within tolerances. Cannot find any vacuum leaks. Looked at the various hoses etc. and all seem to be proper. Removed and installed another Throttle Position Sensor (known to work properly), unfortunately same result.
Tomorrow will do continuity checks for all wiring to AFM, TPS etc. and do a propane check. Need some luck.

[Jiff Lemon]

LOVE the vids! they're fantastic!

Has anything changed on the car recently?
I.e has been working fine then you did XYZ and since then it's been getting worse? or is this post install?

Did the engine come from a known running car or a junk yard special?

The flap closing sound us likely just to be the AFM flap clunking shut as it dies.

[ThreeD]

Convoluted answer follows but is necessary for understanding

Have two MR2s (85 grey & 86 black) seen in my original thread. This engine was in the 86 black: ran properly, in fact went to inspection, but due to various problems the black car did not pass (body stuff). Soooooo, I pulled this engine/trans out (with same wiring harness/ECU/AFM) and installed into the grey.
Engine work consists of: cleaned, installed injector seals/fuel screen per each injector; new spark plugs/wires, dizzy and rotor.
This engine, fuel pump/filter was previously installed into the grey and ran properly (please don't ask why so many engine pulls - VERY LONG, UGLY, :blowup: , MISERABLE, DRUNKEN/WOMANIZING, sure to fit right in with the TwoBrutal crowd, story).

for what it is worth: front radiator fan runs constantly as soon as engine starts up.

[ThreeD]

Update: :freak3:
Engine coolant temp sensor test results:
continuity betw cts and ECU: THW - E8-4 good ; E2 - E8-9 good; resistance @ 180 = .43 kohms

TPS: ran propane through throttle intake at revs - no effect, engine still cuts out (tells me no fuel problem)
Ran continuity tests from TPS to ECU: all wiring (8-1, 8-4, 8-10, 8-11 to ECU) have continuity
pulled temp sensor off when engine at running temp. - no change from problem

The MR2 gods :tease: are having some fun: went to a mechanic friend's shop: opened up this thread to show him the videos of the problem: his computer in the FRONT office ran the video pics WITHOUT sound; the computer in the BACK shop ran the SOUND but no video pics

One question he asked: IF the speedo is mechanical, where is the speed sensor SIGNAL wire (v/y - tapped into the l/r wire from the TPS) receiving its signal - will this affect the ECU? :icon_redface:

[Jiff Lemon]

Speed sensor isn't your problem - Its doing this at idle remember. Only just got back from a long day out, so I need to unpack and unwind, then I'll get the thinking cap on!

[AlunJ]

for what it is worth: front radiator fan runs constantly as soon as engine starts up.

That's..... odd. The front fans don't run off the engine temperature sensor though, so would doubt that theres any direct link between that and the engine problem.

[ThreeD]

Hoping that a symptom may spark a memory or a thought :eusa_think: for a route to take in solving this problem. am no longer clutching at straws - am clutching at the memory of straws - but with PERSISTENCE :fingersx: