Missing Surging please help....

piggiepigg · #1 10-12-2005, 01:33 PM

Hello braintrust,
i've been reading this board for a week now trying to diagnose the problem with my wifes 1996 passport 3.2. i've read hundreds of threads, tried a few things and seem to be digging a nice hole for myself. here we go:

car maint history:
recent oilchange
recent fuelsystem clean
recent coolant flush and fill
recent air filter
new plugs
fairly recent battery

then a month later...

initial problem:
check engine light
decrease in power
surging at highway speeds
spark knocking
erradic shifting
seriously doggy in second gear
starts perfect
idles fine

had the cel code read at midas 80.00
EGR valve problem codes found (forgot the exact codes)
replaced EGR valve 111.00 at autozone (unfortunately before i new i could clean/reuse the old one) had code cleared, problem persists
took back to shop, they did more trouble shooting with diag equipment
swapped in a known good map sensor to eliminate that as problem no change. found however that the voltage coming to the map sensor would suddenly drop to zero and would not increase in voltage when revving motor. the mech thinks at this point it is an ECM problem. i explain also some other querky stuff with the car, gas gauge doesn't work full sweep, tach kicks on only if revving above 5k rpms (indicated at least doesn't sound that high tho), radio won't turn on sometimes. thinking maybe it is ECM

purchased used ECM from boneyard 100.00
isuzu numbers don't match exactly but try it anyways
same problems persist no change sigh..

performed ECM cleaning procedure from posts found here
misted perimeter of intake with starter fluid and all vacuum hoses fittings etc checking for vac leaks, tight as a drum

buy new fuel filter no change
have battery checked checks fine
clean contacts
notice however that dome light dims on hit of throttle, that mean anything to anyone?

it's running worse now than before. surging is happening at low speed and car is undrivable. but sucker still starts first crank and idles great, doesn't smell or indicate warm. not missing or if it is, very subtly. i'm wondering if the ecm i got was also bad, and want to seek out one with exact numbers as mine. the second set of numbers varied slightly like ...294 vs ...296 or something i'll double check that. seems like a modern car running this bad would toss a code again, unless it can't and the ECM IS bad after all. check engine light still works with key in acc position.

also i wan't to hit it with my timing light and see where it's at, if it's in range and if it's changing with rpms.

i wanted to exaust a lot of possibilities before coming to the table, and i think i have. ok boys and girls i'm waiving the white flag. my wife is going to sell ME if i don't get it fixed soon. please help.

php · #2 10-12-2005, 02:40 PM

I'm thinking you may have two problems. One may be your catalytic converter. A bad cat would cause problems at higher rpm's. And/or a bad alternator/battery. From things I've read in this forum, Isuzu's (not sure about Honda's) do weird things when alternator is going bad.

php · #3 10-12-2005, 02:56 PM

pigg- let me know if you solve your problem. I have a similiar issue. I have been trying for a couple of weeks to solve. I have already replaced the cat. I'm going to replaced my alternator soon. I have also changed almost everything else. Plugs, wires, fuel filter, Ignition control module, ECM, MAP sensor, Throttle position sensor, Intake temp. sensor, timing belt, cleaned out EGR and checked for IMG leaks. I'll let you know if I have any luck.

After the alternator (if that doesn't do it), I'm going to double check the timing belt and then go and tear the intake manifold off just to eliminate it as a possible problem.

piggiepigg · #4 10-12-2005, 03:22 PM

i considered the cats, as it is running like it's got a banana in the pipe. can muffler shops do a quick dirty test on cats? just tested the battery at checker and they say it's good, and i imagine if the alternator was bad the battery would go dead, which it definately is not. like i said above it turns over and starts like a top. this couldn't be tranny issue could it? i'm not sure if she's ever had the fluid/filter changed, and i haven't done it.

php · #5 10-13-2005, 10:59 AM

The alternator could be bad and still not kill your battery. According to others in this forum, Rodeo's don't like it when the voltage from the alternator drops below 14.something.

I'm don't know if it could be tranny issue. Never have really had a transmission problem before.

As far as having a muffler shop test the cat, I read something in this forum about it, never had it done, or heard about it anywhere else. That doesn't mean it can't be done. You'll have to call a shop and see.

piggiepigg · #6 10-13-2005, 05:03 PM

just noticed today also that the voltmeter gauge on the dash drops to 12 volts or lower upon revving as well. starting to lean towards the alternator. i'm going to study up here a bit on which alternator to get. sounds like an oem one is the way to go. anybody know what they cost from the dealership? is that where i should go to get one or should i try BAP first?

Canucklehead · #7 10-13-2005, 05:10 PM

Quote:

Originally Posted by piggiepigg

just noticed today also that the voltmeter gauge on the dash drops to 12 volts or lower upon revving as well. starting to lean towards the alternator. i'm going to study up here a bit on which alternator to get. sounds like an oem one is the way to go. anybody know what they cost from the dealership? is that where i should go to get one or should i try BAP first?

The voltmeter dip when revving the engine could be completely normal. Try turning on the headlights, then rev the engine. The voltmeter shouldn't dip when the lights are on. If you have the owner's manual, this is mentioned.

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