brad11140

iTrader: (3)

OK here is the deal. Still dealing with the hesitation issues. I decided to check my O2 sensors with a meter tonight. Did the whole run it up to 2500 RPM's for 120 secs than put your DC voltmeter on VF1(VF2) and E1. It sits at 5.00 volts. The only fluctuation I see is that it will go from 5.00 to 5.01. Is that considered fluctuation that I count. Otherwise it would appear both sensors are not doing their job. I have recently replaced the engine coolant temp sensor.

brad11140

iTrader: (3)

Forgot to mention. I do not have a check engine light on. No codes stored.

brad11140

iTrader: (3)

Pullled bbot main O2 sensors and inspected and cleaned. Replaced with no change. I also checked my MAF. Resistance readings are good. Did a voltage feedback check and its all good. Car runs great with MAF disconnected. like crap with it connected. Since I have replaced my ECT sensor and my TPS calibrated perfectly I think the O2 sensors are all thats left. IAC valve was perfect as well. I checked the voltages again with a better meter and with TE1 and E1 jumpered I get .083 VDC on VF1, no fluctuation and 5VDC even steven on VF2. So I would conclude that the O2 sensors are not working. Just looking for someone else who has seen the same readings.

skirts

iTrader: (1)

Can you do a write up on how to check the O2s? I have an O2 problem as well when it's warm outside. When it's cold I never have a cel.

brad11140

iTrader: (3)

Will do. I am thinking that my engine might be in a lean condition due to the fuel pump ECU. IF you follow the troubleshooting table it has you check voltage. I get 5V. Follow it down it has you put a resistor in the ECT sensor plug and check for voltage again. IF you still have 5V than its a lean condition and it just says repair. Since I have traced my problem to either the fuel pump ECU or the fuel pump I don't think the proper amount of fuel is getting there resulting in a lean condition. If a lean condition prevents closed loop operation than my O2 sensors would not have been functioning. I am just speculating.

iridebmx

iTrader: (6)

does it drive normal until it heats up than hesitates always once warm?

brad11140

iTrader: (3)

I was trying to nail that down. It would hesitate real bad when cold. So than I started letting it warm up real good. Than it started hesitating real bad when warm. I jumpered the fuel pump and it is flawless operation when hot or cold.

iridebmx

iTrader: (6)

nice! fuel pump bypass is always my first instinct with sc's haha

brad11140

iTrader: (3)

It certainly works. I am tired of buying things that don't fix the problem. SO I want to make absolutely sure that the ECU is the problem. JUst because the pump will run in high speed does not mean that its not failing and having a problem running in low speed. After the voltage checks it does appear to be the ECU.

brad11140

iTrader: (3)

Here is an update on the O2 sensors. Maybe this is stuff you guys already know. I decided to recheck my O2 sensors with the fuel pump jumpered. Careful here because to check the O2 sensors you jumper TE1 and E1 as well. Accidentally touch the fuel pump jumper and zap your EFI fuse will blow. don't know how I know that . So anyways, ran it up to 2500 RPM's and checked. Low and behold I get the fluctuations as needed. Pull out the TE1 and E1 jumper and check voltage between VF1 and VF2 to E1 and its like 2.2 volts. Now here is the interesting part. Pull the fuel pump jumper. Now I check my voltage from VF1, VF2 to E1 and its 5 volts. Follow that out and I bet you money it leads to an Over rich condition and this also means the O2 sensors are not functioning. So a bad fuel pump ECU, which I am assuming as of now, will cause hesitation and it is also causing the car to run in open loop or some other weird map.

Stretchp2

Thanks for the final update I will follow this guide regarding my hesitation issues.