73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: zieg85 on August 29, 2009, 04:47:06 pm
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I just picked up a 95 and for the most part it runs pretty good. It is running on all 8 and you can fiddle with the gas pedal to get it to go however it bogs down if you floor it. It has had a tune up with cap, rotor, wires plugs and air filter. Scratching my head over TBI. Any common things to check first?. There is no check engine light. Any help would be greatly appreciated...
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fuel filter, fuel pump
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...regulator, fuel lines...
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Replace the fuel filter and wires too. Check your fuel pressure and report back.
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With a tbi system the ecm makes all the decisions for fuel/air delivery. So if the filters are ok you gotta start thinking along the lines of a sensor being faulty. Vile can walk you thru the troubleshooting steps.
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Thanks for all the support, I've been real busy but Friday is when I check the fuel filter/fuel pressure and I will report findings. I doubt the fuel filter is the problem as I can get it to go down the road fine if I fiddle with the go pedal. It does seem to start hard which maybe could be a weak fuel pump. It will idle fine but put it in gear it will die. When it idles you would think nothing is wrong, it is such a smooth running and quiet. When you give it gas it doesn't seem to miss, just boggy. Kind of hard to put it into words, sorry...
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It should spray good when you crank it to start it. The most important input sensors to the computer are the crank sensor pickup in the distributor, the throttle position sensor, temperature sensor and MAP sensor. It needs reliable information from all of those to run well...of course it needs enough fuel pressure too. I would start by checking fuel delivery, then check the pickup in the distributor - Ive seen a few go bad, and finally the last one I would suggest looking at is the coolant temperature sensor...near the thermostat. It can go bad but still be in a "legitimate" range and not throw a code. I have seen two fail and cause overfueling (Checking with a scanner showed them to be reading well below freezing on a summer day)
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hey let me know it you get it fixed I had the same problem, in park at idle runs good floor it it bogs and will die if you dont let out but if you let out it is right back to a good idle. I replacer throttle Body, all and every sensor on the throttle body and engine, then i gave up and got rid of the thing cause i had to have a way to go *L* maybe if i had been a member here it would of gotton fixed.. *L*
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I had a couple of hours to work on it Saturday. First the fuel filter is fine. I found some really bad vacuum lines that I replaced. That seemed to make it idle great. Starts better also. I noticed it runs better cold than hot so I am going to check the temp sensor first. Still no check engine soon light. I think reverse is going out as it chatters real bad going backwards if you give it gas. I never had felt that on any vehicle I have ever known. My brother in law has a scanner for the older OBD I systems so I guess I'll ask him to take a look.
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Got her fixed. My brother in law suggested to squirt some gas down the throttle body throat to see if it was more responsive. Sure enough the engine picked right up. Changed out the fuel pump and screen in the tank and she runs like new.
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Thats good.