92 KA Problem

[Kevin920415]

Recently I have done a 5 speed swap on my hatchback, and during the process, I cleaned out the IACV and moved couple of lines aside to reach the transmission bolts. Now the problem is when I start my car, it would start normally until it hits near the 700rpm, it would backfire? or bog I should say.
When I gently tap the gas it seems as if the throttle is open for 5 seconds until the rpm drops..

What could the problem be?

Vaccum leak? IACV?

[Silentoreo34]

Could be the IACV getting stuck open.

[hOngsterr]

or possibly its the effects of automatic ecu.


edit ; when driving and coming to a stop, my car revs up and drops to normal rpm.

[andisan]

i have the AT ECU and mine dosnt do that at all, It might be the IACV, i say follow the FSM on how to adjust it and go fro there.

[Ilumis]

Recently I have done a 5 speed swap on my hatchback, and during the process, I cleaned out the IACV and moved couple of lines aside to reach the transmission bolts. Now the problem is when I start my car, it would start normally until it hits near the 700rpm, it would backfire? or bog I should say.
When I gently tap the gas it seems as if the throttle is open for 5 seconds until the rpm drops..

What could the problem be?

Vaccum leak? IACV?

i have a similar problem with my ca - look at my thread. best thing to do first is to spray some starter spray or carb/brake cleaner onto the iac and intake manifold - if idle changes you might have a leak somewhere.

[Frank_Jaeger]

Vacuum leak, more'n likely. Does the car kinda buck? If it's a minor vac leak, it'll shake. If it's major, the car'll turn into a mechanical bull.

Replacing my IACV I cracked my brake booster hose. Also found out a vac line on the EGR was destroyed. Made my idle worse, lol.

[Kevin920415]

it just idles like a rotary.. I have a stron feeling its a vaccum leak from somewhere...I'll try to replace the ecu to manual one since some people had this issue with idling..

[Ilumis]

it just idles like a rotary.. I have a stron feeling its a vaccum leak from somewhere...I'll try to replace the ecu to manual one since some people had this issue with idling..

exactly like mine (expect my ca also stalls..). i am sure its a vac leak at the intake manifold because i can hear a leaking noise and if i spray some starter spray or something similar there idle will improve. i think you also have a leak anywhere - just look at the threads here on the forum -> so many people with fuel injected engines got idle/leaking probs!

its hard to find the weak point because if you have a vac leak for example it could decrease but also increase your engine idle. i think it depends on wheres the leaking spot!? there are so many parts/gaskets/hoses that could cause the problem so you either remove the complete intake manifold and get new gaskets and maybe new hoses or you try to locate the leaking spot and save time and money if you can find it..

like i said spay starter spray or carb/brake cleaner at the manfifold while the engine idles and see what happens!

[Kevin920415]

So I just found out that spare ecu I have is 92 manual ecu. So I hooked that up last night but still the same problem... I guess its coming down to iacv or vaccum leak?

[hOngsterr]

theres a intake hose that goes straight into the iacv, all you have to do is take it off the intake pipe and spray brake/carb cleaner into it, but youre going to have to keep the engine reving or else it will bog out and die.

to check for leaks you have use brake/carb cleaner and spray that around while the motors on to check also.

[Kevin920415]

Update on this...
Took out the iacv again to clean it thoroughly and I cleaned the hose from intake to iacv also. Car ran smooth during the start up when it was idling around 1800-2000 but once it warmed up and dropped below 1000, it started to bog again....

[zerodameaon]

it just idles like a rotary.. I have a stron feeling its a vaccum leak from somewhere...I'll try to replace the ecu to manual one since some people had this issue with idling..

ECU isn't the issue. It has been a known cheap upgrade for years for the manual guys for years. I never swapped my auto ECU over to manual and the car runs just fine for the last year. Idles up then down to normal in about a second, but that has to due with mapping for the torque converter or something like that.
Look at vac leaks, and that tube under the BPT valve going to the EGR. Make sure you adjusted your idle the right way.