Hesitation under load

chris93

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I have a 93 with a 351 and e4od with 192k on it. Yesterday I added sea foam engine treatment to the crankcase and a small amount to a1/4 tank of gas. I then added sea foam spray to the intake via the throttle body per there instructions, which included driving aggressively afterward. After all this I changed the oil and filter and parked it for the night. This morning I leave for work and is hesitating and sputtering, but only when in gear, it idles fine,starts fine and doesn't sputter if you give it gas while in park or neutral. I thought the gas treatment might need to be diluted more so I filled up with 93 octane, normal gas grade selection for me. Everything looks in place under the hood, vacuum lines, plug wires, but driving down the road it will feel like it is plowing power, pops which I guess is detonation and hesitates like it has a misfire. I'm stumped.

 

budster 95

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I never put anything other than Gas in the tank, and oil in my engine. Some of these additives can do more harm than good. Your problem seems like it may have something to do with your TPS. (Throttle position sensor) You will first have to read the codes. See key on, key off, procedure.

 

chris93

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Yeah I've never added anything before and I'm kicking myself now that I have. Help me out, key on key off procedure, might I find that in the Haynes manual?

 

Krafty

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the two tests he is referring to are the Key On Engine Off or KOEO and Key On Engine Running or KOER. these are both computer self diagnostics that display the stored codes from errors or malfunctions for up to the previous 40 trips.

the test procedures can be found in your Haynes manual or the moderators have direct links to several sites that go through the process step by step.

in my haynes manual the testing information is in section 4-14 under, 4 fuel and exhaust systems, 14 fuel systems - trouble codes and self tests (EEC-IV)

good luck.

 

chris93

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Okay so I dont have a voltage meter but trying to follow the manual on the koeo procedure. Just out of curiosity if I take it to a parts store and they run a scan tool on it will they pull the correct code?

 

Krafty

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i've never done it but i believe they can do it. BUT

if you skip the volt meter part... and just run the one jumper wire, the check engine light on the dash will flash the same way a voltmeter would.

my multi meter is broken so thats what i did, all you need is the 4" piece of wire, also by being in the vehicle once the KOEO test is done then you just turn on the engine and let it do its thing for the KOER test.

 

chris93

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It looks like a test light will work too. Oi electrical stuff always makes me gun shy.

 

Krafty

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lol just remember its easier to write down the codes if your not holding something in your hands like a test light.

good luck

 

chris93

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Okay so I used a jumper from what I thought was the signal return to the sti for the eec test jumped in the truck and turn the key to run but not engine start and the check engine just stayed on the whole time. I did not try to do the koer test as it is way to cold out right now. Am I missing something here or what?

 

chris93

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I'm also thinking that this sea foam stuff dripped down and fouled my tps,since it is located below the butterflies in the throttle body. I was thinking maybe some throttle body spray cleaner might help.

 

Krafty

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okay sounds like you just got one wire crossed.

on the picture below the jumper wire goes from the self test connector to the #2 connector on the plug. and thats it.

it will work.

EADiagnosticproceedure.jpg

 

chris93

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Okay I must have one of them mixed up I was jumping the two terminals on that same plug labeled eec test. I'm guessing that is the number two terminal. Where is the self test at?

 

chris93

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Sweet! I've noticed that before while poking around under the hood. Thanks for pointing me in the right direction. How important is it to have the engine warmed up? You leave the jumper attached and engine running to run the koer test as well correct?

 

chris93

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Yeah that was my initial thought too, but everything appears intact, but I will double check for any damaged vacuum lines

 

chris93

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Okay so that gave me a code of 542, now I need to find out what that means, haven't been able find that in thar haynes manual.

 

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