I can't figure out what's going on with my k5. Its a 87 TBI 700r4 . the truck runs great. It will even spin the 35s without even thinking about it, but put her in drive and hit the road and it dies! Starts right back up try and drive and dies! I've replaced a lot of parts and have no idea why to do next! New parts... Fuel tank ,pump ,lines, coil, egr, IAC , cap, rotor, plugs,wires, ignition control module, neutral safety, and ecm... Please help!!! Oh no codes either!
CK5
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desperately need help!
- Thread starter 87vandal
- Start date
How can you spin the tires if it won't keep running in drive?
We need some better description of what's going on.
We need some better description of what's going on.
Shot in the dark, but how did you set your timing?
An EGR valve can act that way, if you replaced it, make sure you get an AC Delco for best performance, they are expensive but fit and work correctly. If you used a generic you may still have the same problem, I found that out the hard way, twice even!
No codes is a good start.
2 things need to be done next, one was already mentioned is setting timing. ECM has no idea what you set timing at the distributor and it get's set to 0* with bypass wire disconnected.
Then fuel pressure. GM says 8 or 9 to 13 PSI. My experience shows anything below 12 sucks! The ECM can correct, to a point for lower or higher pressure. But like spark it has no idea what it is and expects it to be correct.
2 things need to be done next, one was already mentioned is setting timing. ECM has no idea what you set timing at the distributor and it get's set to 0* with bypass wire disconnected.
Then fuel pressure. GM says 8 or 9 to 13 PSI. My experience shows anything below 12 sucks! The ECM can correct, to a point for lower or higher pressure. But like spark it has no idea what it is and expects it to be correct.
The fact that it works when you try and brakestand makes me wonder.
It woudl be easier to figure out if it didn't work at all.
How did you measure timing? Proper timing light?
How'd you measure fuel pressure?
It woudl be easier to figure out if it didn't work at all.
How did you measure timing? Proper timing light?
How'd you measure fuel pressure?
does it rev properly in neutral?
Well that is in the ballpark and should not be an issue.
Check codes again!
From your symptoms next thing I would look at is TPS voltage, this can be done with a scantool or DVM by back probing. Voltage at throttle closed should be close to .54v and then open throttle slowly and voltage should rise smoothly to around 4.50v.
If there is a TPS issue it should show up in codes, but this is not absolute.
Check voltage again by moving throttle same as when problem is, look for spikes/drops?
When you say no codes, do you mean the CEL is off, or did you actually try to pull hidden codes?
On that 700r4, is there a vac connection to the motor of some sort?
4xcrazy
3/4 ton status
11psi seems a touch low to me, I know it's technically within spec, but did you check the fuel pressure and watch it while revving the engine to make sure it maintains or pressure comes up some during engine acceleration?
this is a shot in the dark,i have no basis to back this up,just throwing this out,possibly a vss issue,,,variable speed sensor????
4xcrazy
3/4 ton status
And this thing restarts every time it dies out? No problems or hard starting right after it shuts off?
