CHM

My 91 MAX GXE has been idling a little rough and generally speaking, has lost power, especially going up hills. I checked the ECU and in Mode I get no light at all (no blinking) and the same happens in mode II. In mode III, I get the 21 and 33 error codes. 21 is the ignition signal circuit and the FSM says to check the harness and power transistor unit. 33 is the exhaust gas sensor circuit. The fsm says to check the harness/connector, sensor, itself, fuel pressure, injectors, and intake air leaks. I do not have intake air leaks. I did not get any injector error codes and all of the injectors have been replaced already about 30 k miles ago. I have also replaced the engine 2,4,6 injector subharness and am waiting for the repair kits for the other harnesses. Anybody have similar issues or other suggestions? THANKS

GRNMAXDMON

iTrader: (1)

check for the green corrosion on ur injector harness and clean them off. while the injector harnesses r unplugged crimp down just a bit onto the female connector to get a tighter fit. then go to ur Coolant Temp. Sensor and do the same thing. as for ur code 33 thats for the O2 Sensor. u can either clean the O2 sensor or replace it. ur choice though. i encountered the same crap with my Max a week ago and my boss just did what i just explained for u to do. and it worked out fine. so good luck and let me know what happens.

CHM

Thanks. I already checked the ignition coil. It's fine. Checked the power transistor - also fine, in terms of continuity. I will check the resistor today and change out the 1,3,5 injection harnesses when I get the kits. As for the O2 sensor....I need to check the harnesses and the likely replace it. Sounds like that may be the problem? I also need to change the timing belt soon. I was not planning on replacing the tensioner and oil seals, etc. But, is should I? Does everyone change the oil seals too? I wonder how often there are actually harness/wiring problems. Do people often actrually check the continuity between ECU and harnesses? That seems like a royal pain..

Wiking

Never done that. ECU harness is the last to go. However, Connectors...

Tuneup time: Cap, wires, plugs, distr GND, IACV, connectors cleanup, etcetc.
clic& read http://www.cardomain.com/ride/748507/1

Belt: one crank rotation = half cam Cam rotation. If theres any indication to wear, crank seal is to be changed twice when cam seals once. The seals are only cheap things in a max, replace...

GRNMAXDMON

iTrader: (1)

once u do change the t-belt just take the extra time to change the cam and crank seals. they r cheap and easy to install so just change them.

vansskaterfreek

iTrader: (14)

my canshaft seals were a pain in the ***. i had to fabricate a mechnism to get it out.

GRNMAXDMON

iTrader: (1)

yeah that sux. luckily i changed my seals while i was doin' motor swaps on both my '93 and '89.

CHM

Any other ideas on the O2 sensor? Would a bad injector or fuel pump pressure issue, etc. trip the 33 code? I really don't want to spend $100 on a O2 sensor and not fix the problem. The injectors have 30 K on them, so I hope they are OK. There is no injector error code. I greatly appreciate your comment! I'll look at the canshaft seals and decide if can get them out without causing more damage.

Wiking

...already said, detailed: test DIY -and/or- lease buy autozone obdI tester.

ECU is like lottery machine: most often it gives nothin.

internetautomar

iTrader: (30)

the o2 is only about $60.
injectors are more, and the only other thing that may trip the code is bad wiring

GRNMAXDMON

iTrader: (1)

if u can get ahold of a fuel pressure regulator and hook it up to ur fuel lines and start ur car and it should read between 34-40 or 45. if u c that u get any of those readings then ur fuel pressure is fine. thats how i knew my fuel pressure was fine.