vtec cuts out while driving

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98civicproject

New Member
i have a gsr in my 99 si that i just recently bought. when i do a run down the street, the vtec will kick in when im in gears 1 and 2. but when i grab 3rd and around 5000 rpm the check engine light comes on and no vtec. after that the vtec wont come on at all.

whats the problem. im completely baffled. sensors maybe.idk, plz help
 
ok, the car runs good all the time, i cant tell if i have an oil pump problem either. its just the vtec and its very frustrating. anything else.

the only time i get a check engine light is only when i hit vtec.
 
when my head gasket went bad it did the exact same thing cuz the water n oil were mixing which made it lack the pressure to switch over. not saying thats the problem but just listing my experience of a road that ive been down. do u throw the cel which code did u get?
 
check your oil level first of all.... if you are low on oil, you will lose oil pressure, and vtec no workie.

and yeah other than that, you need to figure out that CEL, it will point you in the right direction if its a sensor.
 
my oil is good bro. i did notice i am missing a iat sensore that goes on the intake manifold. could this cause it.

along with the head gasket i do have a little leak around the head but shouldnt cause any problems.
 
how many miles on the engine?

the oil leak, what side is it on and how bad?

Have you replaced the vtec solenoid gasket? Also check if the screen is clogged up.

Ever ran low on oil?

Have you checked your grounds?
 
ive checked all of that but the screen. could a clogged screen do this. this is so frustrating what i have going on here.

i bought this car a couple weeks ago. its a 99 si with a 95 gsr motor. the ecu is a chipped p28. wtf why did he use a p28. he also has a jumper harness from the ecu to the main harness. i cant tell if the motor wiring is obd 1 or its the computer thats obd 1.are all 95 gsrs obd1
 
Update... i just talked to the previous owner and he informed me he bought the car in texas. he drove all the way back to colorado, where i live now. he said everything worked on the drive back until he got into higher elevation then the vtec was screwing up. he was told something about a baro sensor (atmospheric pressure sensor)

could this be the problem.
 
Buy a p72 ecu or get that p28 chipped with a stock base map.

What cel are you throwing anyway?

BTW I think this guy is Full of it. Shitty way of converting a from obd2 to obd1.

Yes all 95 gsr's are OBD1. 93 to 95 is OBD1 in Acura.
 
i couldnt pull any codes becuase its a obd2 reader. i need to go somewhere else to get codes pulled. but concerning the ecu where could i find a p72. i just dont know how to go about fixing this.

if get a p72 i prolly have to reping everything, i hope not. i have a friend who can program my p28, should i go that route.
 
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i have a 99 si w a 95 gsr. i checked my codes using the two ping connecter under the dash and it didnt flash any codes. the cel just stayed on.
 
Find a way to check the codes, That would help a hell of a lot.

Now did the check engine light stay on? or did it flash?

Also you need the engine off, but have the key on the "on" position.
 
Right, I did it on a 1999 EK hatch once and it worked first try.

Check if it really a P28 ECU. Maybe something went wrong in the OBD1 converison.
 
the light stayed stayed on, didnt flash either. what i dont understand is the previous owner told me its a 95 gsr motor which is obd 1, but has a p28 obd1 with a jumper to the harness.

how is this a conversion, is got to be one or the other. i had to id my ecu because it has no markings but a faint smere which made out chipped p28. that ecu, according to pics on the net, is a obd1.

what the hell do i have going on here.

were gonna try the obd1 reader today. crossing my fingers.
 
its a obd1 motor and ecu in a obd2 car, thats why u have the jumper harness. id say its the factory si harness in ur car since its done that way...
 
If you jumped the harness and got a solid CEL with no blinks....then that means (to me) that you have no codes.

And you already checked the screen on the VTEC assembly? No leaks? Everything else is fine? Idle and such? Might need to try another VTEC assembly as a test/experiment.
 
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