engine boggs down when revved

[Mr. Joe]

So i recently bought an '88 Supra turbo with a low mile JDM engine swap. The car ran fine until a couple days ago it suddenly had trouble revving up when i pressed the gas pedal. Slowly pressing the gas pedal will rev it up a bit but quickly pressing it causes it to almost die. It had a funny smell at first but i haven't smelt it since it originally began having problems. After doing a diagnostic test it gave me codes 31 (AFM related) and 43(starter related). I thought it was a boost leak so i changed one of the intercooler pipes and reset the computer. Now the test only gives me code 43 but it still has all the symptoms. Often times, the car will fall to an idle of around 400 rpm and the engine shakes. Anybody have any ideas?

 

[hvyman]

Afm might have taken a dump.

 

[suprakidd]

for intake leak after the afm...

 

[Mr. Joe]

I was thinking that it might be the afm as well, but wouldn't the code for the afm still come up when running the diagnosis?

And one of the pipes i changed was the pipe between the afm and the turbo because it had a crack in it but the problem was the same after changing it.

 

[jonahs_supra]

ive had my fare shares of bad afms
everytime 1 went bad on me it was the temp sensor inside the afm

now im speed density...still have a good afm laying around
PM if yours is bad

heres a test

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

 

[jetjock]

Smelt is a fish...

 

[Mr. Joe]

I got a new AFM and so the rpms no longer drop when I give it gas. However, the car seems to have trouble building boost. It luggs at around 3000 rpm and the boost gauge doesn't read anything. I was thinking that it could be a boost leak but i've tightened down all the clamps and the hoses still look like they're good. Any suggestions?

 

[Poodles]

Squeeze them. They usually split in such a way that closes itself up when it's just sitting there.

 

[jonahs_supra]

I got a new AFM and so the rpms no longer drop when I give it gas. However, the car seems to have trouble building boost. It luggs at around 3000 rpm and the boost gauge doesn't read anything. I was thinking that it could be a boost leak but i've tightened down all the clamps and the hoses still look like they're good. Any suggestions?

i have yet been able to master finding a boost leak by looking

 

[Nick M]

Thankfully, Toyota knows when you have an intake leak and stores 34 for your convience.

 

[jonahs_supra]

Thankfully, Toyota knows when you have an intake leak and stores 34 for your convience.

and we thank them

 

[Numba1Stuna]

My car was doing something very similar, in fact I posted YouTube video of it running to get advice. I had the same issue of it bogging down when mashing the gas, but slowly stepping on it would allow me to get nearly to red line. Turned out to have poor compression, and a cracked block. Hope that's not the case for you. Here's the video of what mine was doing. Hope it's helpful for you.

https://www.youtube.com/watch?v=lKPQ5eJhHcY&feature=youtube_gdata_player

Sent from my LG-P999 using Tapatalk 2

 

[zby67]

for intake leak after the afm...

this is what happend with my MKIII when i looked at it look like someone took a razor blade to the hose after the AFM...

 

[Mr. Joe]

I'm beginning to doubt if the problem is a boost leak. I was convinced that it was until I replaced the intercooler hoses with the metal ones that came with an aftermarket intercooler that I got when i bought the car. The problem had not changed at all. The car still lurches forward when driving but it still can build up boost. I'm guessing that it could be the fuel pump, so does anybody disagree?

 

[Mr. Joe]

I just thought I'd clarify the symptoms so here's what the car is doing now:
hesitates and then lurches foreward starting at about 2500 rpm and continues to redline (acceleration is more like a step staircase than smooth slope)
aside from the unfluent acceleration, car seems to have the same amount of power as before all the problems began
only engine code that comes up is 43 (i don't think that it has anything to do with the problem because according to TSRM it has do do with the starter)

 

[jonahs_supra]

hows it idle? smooth?
did you test the new afm per tsrm?


also i just remember the E1 ground wire running to the afm on my 87 had a break in it
causing my car to run good sometimes and like shit other times
ran a ground wire to the passenger fender well...presto no more issues

 

[Mr. Joe]

yes it idles smoothly but i did not test the afm. I know that the afm is good because it came off a car that ran perfectly. did your wire look bad? because from what i can tell all my wires are fine.

 

[Nick M]

also i just remember the E1 ground wire running to ......ran a ground wire to the passenger fender well...presto no more issues

Just don't do that with E2. However, bad grounds can cause a lot of problems as is being pointed out, like right here.

 

[uncmk3nut]

Here is my 2 cents.. I was reading this thread because my mk3 had similar symptoms recently. I replaced the fuel pump with a 255 walbro, then the car would drive fine until I hit boost, so I had to do the 12v relay mod for the fuel pump resistor and now no more fuel cut. However, before I installed the fuel pump; I had to rewire the knock sensor because it was making the engine bog down when the throttle was pushed more than 20% (sometimes less or more). This of course might not help you but it was my problem.

 

[Numba1Stuna]

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