4age not reving past 4000rpm

[evil86]

hi, i currently have a problem with my 4age. its a jdm 4age bigport with tvis. i just put it in my ae86 and now it doesnt rev past or struggle to get to 4,00 rpm. motor came from a work jdm trueno. timing its all right, set at 10 degrees

[Sprinter86]

sounds like the ecu may be in limp mode? i would start by checking the ecu for codes, then go from there.

[Javal]

sounds like the ecu may be in limp mode? i would start by checking the ecu for codes, then go from there.

Agreed with this.

Do you know any history of the engine? i.e. has it come out of a mates car or is it fresh off the boat?

[evil86]

motor come out of my jdm trueno. was running sweet. im gonna check plugs to see if they are fouled. how do i check for code on the ecu

[MINIHORSE]

id say check pins on TVIS plug, from memory mike86 had a similar problem, due to the fact TVIS kicks in yo!! at 4200, hope this helps

[Trev084]

Where you located?

[reecegze]

Could be this or plugs are fouling at high rpm , causing engine to miss/drop cynlinders or run in limp mode



id say check pins on TVIS plug, from memory mike86 had a similar problem, due to the fact TVIS kicks in yo!! at 4200, hope this helps

[Nikkojoe]

Sounds like limp mode. One possible cause is a map sensor fault. Check the connections to the map sensor (electrical and vac line). Simple test is to unplug map sensor and see if the engine stalls. If it stalls, map sensor is working fine.

To check codes:
If you have not got an engine check light on dash, use a test lamp. Find the pin on the 3rd ecu plug which corresponds to the check engine light. Connect one end of the test lamp to +ve 12V, the other to the check lamp pin.

On the engine loom, the diagnostic connector on a zenki is near the a/c piping on the firewall. Its a little round plug with 2 pins (wire colours are blue/white(TE1) and brown (E1)). Kouki have a diagnostic box, but with more pins inside. All you need to do is bridge these two pins together (TE1 and E1) and then turn the ignition to on position. You will see the test lamp flash/check engine light flash. Have a look on club4ag website for list of error codes and what the flashes mean.

[evil86]

i took out the map and it didnt stall, i have 2 map sensors 4age and 4agze and when i put them in they dont rev past 4000rpm and when i take them out they dont stall

[Sprinter86]

get codes before you start muckin around changin parts IMO.

[evil86]

i went to a mechanic and he said its a code 2, whats a code 2?

[Sprinter86]

http://www.toymods.net/forums/showthread.php?t=21739 have a read of this, it should alow you to acuratly find out exactly what code the ecu is producing mate.

[evil86]

damn, its kinda confusing aye, as im a noob to engine problem.

when diagnostic test was done. light flashed 2 times then stops then flashes 2 times and repeats itself. when i drive it, idle goes up n down from 1,500 to 2,00 rpm. and max revs is about 4000-5000rpm.

[Javal]

id say check pins on TVIS plug, from memory mike86 had a similar problem, due to the fact TVIS kicks in yo!! at 4200, hope this helps

Even with TVIS inop the motor will still run past 4000 rpm.


i went to a mechanic and he said its a code 2, whats a code 2?

Could be a code 22 - water temp sensor? although the symptoms you describe aren't synonymous with the symptoms of a bung water temp sensor.....

In what way is it not revving past 4000? straight cut out, starts misfiring? etc?

[evil86]

starts missing, popping noise

[skit]

My guess, your engine is not getting enough fuel.

I thought that before you mentioned that it starts popping.

Check the washers around your pulsation damper (inlet to the fuel rail) are orientated correctly. I ditched mine in the end, it was temperamental; sometimes it would not flow properly, pending its orientation (I ground off the stopper so I could spin the damper fitting around so my fuel line cleared my throttles).

The only factory ae82 bigport engine I have here doesn't have one anyway, so not sure why jdm bigport rails have them.

[evil86]

with my ecu im getting a code 2 ( flash 1.5s pause flash 4.5s pause then repeats) with another jdm ecu im getting a code 1 ( flash 4.5s pause then repeats. )

does code one mean its working fine?

with the code 1 i then took out the STOP fuse at drivers kick panel for 10+ seconds and put it back it, still same problem.

but when wire is still connected to T and E1 on code one and i start it and runs fine, but engine light flashes (keeping in mind that the T and E1 and still connnected

[reecegze]

code 1 is fine its normall. When you have it bridge it will show code 1 if theres no problems. You have found your ecu is giving you a code 2 error but another ecu is saying its fine code 1 "normal" Try to put your ecu back into your car and pull the stop fuse out again this will rest the codes already in memory. You gotta rest code faults after you fix them otherwise you wont no its fixed

[Javal]

with my ecu im getting a code 2 ( flash 1.5s pause flash 4.5s pause then repeats) with another jdm ecu im getting a code 1 ( flash 4.5s pause then repeats. )

does code one mean its working fine?

with the code 1 i then took out the STOP fuse at drivers kick panel for 10+ seconds and put it back it, still same problem.

but when wire is still connected to T and E1 on code one and i start it and runs fine, but engine light flashes (keeping in mind that the T and E1 and still connnected

The ecu must see certain parameters before it logs a fault code, which i guess that if the test ECU didn't fix your problem, it didn't see those parameters yet.

From your description i'm beginning to think your problem is ignition related... poor coil grounding maybe? did you change the coils over from car to car with the engine?

[Nikkojoe]

Well if it did not stall, then you have a map sensor fault and ecu is using a base map to keep the car running. 4agze map sensor wont work, its for pressure not vac.

Check your actual engine wiring harness and make sure on of the map sensor pins has not dislodged. This happened to me and engine ran exactly like yours, misses at idle/partial throttle/at 4000rpm, not reving past 4000rpm.

[Trev084]

Well if it did not stall, then you have a map sensor fault and ecu is using a base map to keep the car running. 4agze map sensor wont work, its for pressure not vac.

Check your actual engine wiring harness and make sure on of the map sensor pins has not dislodged. This happened to me and engine ran exactly like yours, misses at idle/partial throttle/at 4000rpm, not reving past 4000rpm.

A 4age will run without a map sensor, If its hunting at 4000rpm then I would be checking the TPS.

[Golberg]

I had something stupid happen with my engine where it wouldn't get over 3500.

Turned out when I put the fuel tank back in I had somehow managed to crimp the rubber main hose from the tank underneath the tank. Soon as I loosened the straps holding the tank in it ran fine.

[Nikkojoe]

A 4age will run without a map sensor, If its hunting at 4000rpm then I would be checking the TPS.

If you read what I posted I technically said that. He also said it was hunting at 1500-2000rpm which is a common vac leak problem (possibly linked to the limp mode issue). Tps tries to retain closed throttle status so it cuts fuel when the idle gets too high (causing the hunting).

Its running in limp mode, no doubt about it. The ecu is forcing this base/safe map as it's detecting a serious issue (confirmed by disconnecting the map sensor causing no change - the engine should stall if map sensor is disconnected). Make sure all earths are good and all the sensor earths are fine.

[evil86]

i changed the map sensor and ecu and now im getting a code one... but its still not running properly...


any ideas?

[Nikkojoe]

Loom earthed properly? No visible damage to the loom? Check the continuity of wires from sensors to their corresponding ecu pins and make sure none (other than the earths) are earthing out.

[seek]

i had this exact same problem when my 4age got thrown it... basically took 3 weeks of pulling shit apart and seeing what would be wrong... after going over EVERYTHING, i found it that if the engine was running, you could move the wiring loom and the engine would stall (lol...) anyway, Medicine_Man came round and rewired everything, including the MAP sensor wiring as it was your average twist-n-tape job, and it sings a perfect sound ever since.

id seriously reccomend you check all earths, proper wiring terminations, and TPS and MAP sensor wiring. all of this caused the exact symptoms on my engine, and redo'ing it all fixed it.

[evil86]

thanks for that, ill definately will check for earths in the loom,