First Wheeling Trip in a 62 - I had issues (1 Viewer)

[White Stripe]

Sounds like the transmission might be slipping. How many miles on the transmission? Does the engine have a stock tune?

 

[adman02]

Sounds like the transmission might be slipping. How many miles on the transmission? Does the engine have a stock tune?

Probably about 160K. Stock engine with mostly stock tune (slight variations to smooth out tables and such, but nothing wild).

 

[White Stripe]

Probably about 160K. Stock engine with mostly stock tune (slight variations to smooth out tables and such, but nothing wild).

Without driving it that's all I can tell you. Maybe take it to a shop or tuner for diagnosing.

 

[adman02]

Without driving it that's all I can tell you. Maybe take it to a shop or tuner for diagnosing.

I appreciate the help. I just need to find some time to do some diag. My latest theory is that maybe there's a voltage drop at the pump. Anyway, just need to do some work on it. I'll post up whatever I find.

 

[dbbowen]

If its fuel, screw a pressure gauge onto the Schrader valve on the fuel rail to test fuel pressure at the rail. You want to see 58 psi. If you dont have 58 psi your fuel pressure regulator might not be doing its job or you dont have one that regulates to 58 psi, or you have an adjustable one and its not adjusted right.... or your fuel pump isnt fuel pumping right. Your fuel filter could be clogged as well, but this is less likely honestly

The reason i asked if your trans was an AT is because if you dont have enough fluid running through the valves you can get some weird results with the 4 speed gm transmissions.

With the tune you can hook up a wideband and see how your AFR is looking like at WOT or under load. Its hard to say its a tuning issue, because i drove my truck for like 2 weeks with a stock tahoe tune on it with nothing done to it and it drove and accelerated just fine.

 

[adman02]

If its fuel, screw a pressure gauge onto the Schrader valve on the fuel rail to test fuel pressure at the rail. You want to see 58 psi. If you dont have 58 psi your fuel pressure regulator might not be doing its job or you dont have one that regulates to 58 psi, or you have an adjustable one and its not adjusted right.... or your fuel pump isnt fuel pumping right. Your fuel filter could be clogged as well, but this is less likely honestly

I did test the fuel pressure. It's dead on 58 at idle, but when I rev the engine, the pressure drops to around 20 PSI.

The reason i asked if your trans was an AT is because if you dont have enough fluid running through the valves you can get some weird results with the 4 speed gm transmissions.

I'm just hoping I didn't smoke the transmission by having a low fluid situation.

With the tune you can hook up a wideband and see how your AFR is looking like at WOT or under load. Its hard to say its a tuning issue, because i drove my truck for like 2 weeks with a stock tahoe tune on it with nothing done to it and it drove and accelerated just fine.

I did chat with the tuner and he said everything looked fine from a tuning standpoint. He said the smoking gun is the low fuel pressure. It's got to be one of three things: poor flow (clog or small lines), voltage drop (wiring?) or dying pump.

I did notice some pinging under load, which suggests a fuel issue (rather than transmission). I replaced the knock sensors with new GM units, so I'm fairly confident they're in working order.

I just need to get motivated to do some diag.

 

[dbbowen]

I did test the fuel pressure. It's dead on 58 at idle, but when I rev the engine, the pressure drops to around 20 PSI.

I'm just hoping I didn't smoke the transmission by having a low fluid situation.

I did chat with the tuner and he said everything looked fine from a tuning standpoint. He said the smoking gun is the low fuel pressure. It's got to be one of three things: poor flow (clog or small lines), voltage drop (wiring?) or dying pump.

I did notice some pinging under load, which suggests a fuel issue (rather than transmission). I replaced the knock sensors with new GM units, so I'm fairly confident they're in working order.

I just need to get motivated to do some diag.

yeah defintely safe to say its either fuel pump or regulator. the filter/regulator is cheap enough that you could probably just replace that for peace of mind honestly.

 

[cruisermatt]

is the filter/regulator a genuine Wix or knockoff? Have seen quite a few issues with the knockoffs lately.

 

[adman02]

Probably a knock-off. Bought it from Summit and it might be their house brand?