I have a 90 si with a d16z6 with a p28 ecu. The problem that i have is that when i am just driving along and take my foot off the gas, the CEL comes on solid. The car starts running in safe mode and vtec doesn't work. Well i thought that i had solved this problem already, my speedo wasn't working and i replaced the cable and now it works. the cel hadn't come on for about a week and a half and vtec was working perfectly. now all of a sudden it has started all over again, same symptoms, but everything works. i had noticed that some whires leading to the ecu were frayed, so i fixed that. I have reset the ecu, not only by unplugging it but also by disconnecting the approiate fuses and battery.

Can someone help pls. It is getting anoying driving around with a car that has vtec, but doesn't work.

Could this be a bad o2 sensor? Would this cause it to run in safe mode? And in safe mode, does vtec work or not?

 

what code is it throwing?

 

You need to figure out what kind of code the ecu is throwing. When the CEL comes up it is throwing a code. My guess would be code 17 (v.s.s.), but I'm not sure about that, it would also cause vtec to not work.

1. Figure out what code you have, since you have a p28, here is how to check it: http://www.c-speedracing.com/faq/06.php
2. Click the appropriate link to which code you have here (these are 4th gen ecu codes): https://honda-tech.com/zerothread?id=468260

 

i don't know how to check what code....there is no led on the ecu, and the cel stays solid. i don't see any jump wires coming from my harness either. i disconnected the ecu when i got to work this moring and at lunch just hooked it back, runs fine now, but only for a week probably then the probs all over again.

 

Mach69, i will check that out. i didn't know about that plug. i will go out to my car and see if i can't find it. thanks for the info and links......

 

From what you described, it is a code 17.

Trying following this to solve the problem:
Page 1:http://www.we-todd-did-racing....3D%3D

EDIT: Check the speedo cable in the back of the cluster as well FIRST, before doing what it says on that page.

 

Mach69 well i found the plug, put in a paperclip and still didn't get a code, guess since i pulled the ecu all morning long it reset itself. so i guess i have to wait a week until it codes again....but thank you for the help, everyone on ht rules....you guys are awesome.....