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Old 08-07-2011, 07:08 PM   #1
88SuburbanMONSTER
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Unhappy 88 Suburban wont idle

88 Suburban wont idle. Going down the highway, let off the throttle and it died. Timing was off and warped some intake valves. (found while trouble shooting.) Replaced all pistons, all intake valves, TPS, AIC, MAP, EGR, egr solenoid, coil, pick up coil, ignition control module, plugs and wires. Checked for vac leaks, checked fuel pressure (13#) I think that is good for this TBI. Rebuilt fuel regulator and TBI gaskets. Injectors seem ok, good spray. As you can see tons of money already. Any ideas?
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Old 08-08-2011, 08:30 PM   #2
scotts62
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Re: 88 Suburban wont idle

has to be either vacuum leak or fuel. have you put a vacuum gauge on it and see if the needle bounces around?
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Old 08-08-2011, 09:08 PM   #3
ChevyTech
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Re: 88 Suburban wont idle

Did you unplug the set timing connector when you set the timing?

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Old 08-09-2011, 12:04 AM   #4
88SuburbanMONSTER
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Re: 88 Suburban wont idle

No Scott, I haven't put a vac gauge on it; but that sounds like a good idea. may take a day or so ; but I'll try that. As far as the timing advance wire, It seems to be close just by initial time, at least enough to keep it running. I just can't run it long enough to fine tune it yet. Thanks for your replies and I hope to get more ideas in case this doesn't resolve it.
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Old 08-09-2011, 10:11 AM   #5
ChevyTech
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Re: 88 Suburban wont idle

Unplug the hose to the EGR and see if it helps.


The next thing that comes to mind is that it may have valves (rockers) adjusted to tight.

If you used the method in the manual that tells you to spin the pushrod in your fingers when you were adjusting the valves, you could easily have them adjusted to tight.

If the parts are smooth, and you use good lube on reassembly, it is very hard to feel the point your reach zero lash when spinning the push rod. I only use the wiggle the push rod method when adjusting valves.
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Old 08-09-2011, 06:25 PM   #6
88SuburbanMONSTER
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Re: 88 Suburban wont idle

Rockers too tight may be a possibility and I will check that too on Thursday; but before I put the new intake valves in, It was running ok. Then one day after going down the interstate (8 miles) I lost the ability to idle once I let go of the throttle on the deceleration ramp. Has not idled since. Also puchased a vacuum gauge, fuel gauge, and OBD1 scan tool today; which I will try Thursday.
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