My friend has an 03 Evo, today i got a call from him saying the car is acting up after he had hit a hard bump on the road. I told him to bring the car over to look at it. The cars problem is that it starts stuttering when is being boosted more than 10 psi, its kind of like back fire but constant. It sounded and acted just like when spark plugs go out. We went to the store and got new spark plugs, when we took the stock ones out, they were done. Immediately we changed themand gapped them correctly and took the car for a ride. The car cleaned up a bit but its still back firing like crazy. I had asked him just out of curiosity if he had put any other kind of fuel and if he was boosting it. He said he used 89 Oct and was boosting like normal.I right there tought it was the problems but he had emptied the tank and put 93 on it. The problem also sounded like when a hose its lose and the car boosts but at the same time it hesistates. We got under the car and looked at the hoses and seemed fine.

Changing the plugs didnt work. Tighten all the hoses, that didnt work. The only thing i can think of is that he might have punctured a hose or a fuel line from the hard hit the car took in the bottom. We will be changing the hoses tomorrow to see if this works.

Any suggestions are appreciated. Thanks

 

Bump!

 

Is there a CEL? Did the car take a hit or did he just hit a pot hole?

 

Check and make sure that the BOV is seated good. 12 lbs and over a leaking or miss seated BOV can be trouble. Make sure he didn't bust the O2 sensor.

Any mods? What kinda "bump"? Pot hole or ran over a curb?

 

Has no CEL, well it does but its from having no cat. Mods are catback, test pipe, mbc and aps bov. He ran over those things that are round on the road but this one was high as hell for some reason, he tried avoiding it but couldnt bc of other cars. I will check the 02 sensor and the bov to see if it helps. He says this started to happen right after the car took the hard hit.Id imagine it hit the bumper but it cleared it and the hit was taken under the car. i can only think is that he pinched or messed up a fuel line or a hose but it can be something else also.

Weird thing is that at first it didnt want to boost at all and he reset the ECU and then it started to boost at 10psi. After the spark plug change it boosted to 15psi but still hesitated. Sometimes it runs clean but most of the time it hesitates and backfires like crazy....

 

Get the CEL code scanned anyway from autozone because you can't be 100% sure its from being catless. I would dump some c16 in there to get rid of any traces of crappy 89. Good lcuk.

 

I heard of these same symptoms with a guy who had a fuel pump that wasn't installed correctly. So, it would be a good idea to check the fuel system.

 

You might want to check the coilpack as I have seen them burn up before. If thats the case then your friend's car is misfiring big time.

Tom

 

Thanks for all the replies guys

 

Well we came to the conclusion that it has to do with the fuel system, bc the car is leaking fuel that we saw in the driveway the other day. Since it took a hard hit from under the car, im guessing either a fuel line got punctured or the gas tank did. Hes taking the car in for warranty for the problem.

 

fuel pump is shoot

this happen to my friends evo it wouldnt pass 12psi change the fuel pump didnt do it again

 

maybe one of the intercooler pipes came off? i would check that first since it doesnt involve money but im sure u guys wouldve seen it, just a suggestion

 

We have checked that, the car is leaking fuel, but we need to find out where from