Parts Testing

[roshfe]

Hi:

I have a few things in the car that I would like to test out and was hoping that I could get some ideas as to how to do it.

Car is an 88 PulsarNX (EXA) with a CA18DE - Automatic

How can I test...

CAS
Coil Packs
That the plugs are actually firing
Power Transistor
Air Flow Meter


Any direction that can be provided for any/all of these items would be greatly appreciated.

Thanks

RoShFè
:hitwall: :confused:

[TTriX]

most people will tell you to do an ECU test on your ride...that will show you if anything is off.
if you just want to make sure they are all working, that would be the way to do it.
but if you have the parts out and want to check them pick up a manual or find someone who has the specs...
T
if you need parts to swap to see if if that is your fix...i have lots of them-spares-hehe

[Lonx]

CAS - would be very likely to make you car run very rough or almost not at all, as it controls the timing of the fuel injection. I've installed mine up to almost 180 degrees out of place and she's very difficult to start then. If you carry out the ECU diagnostics it will check this.

Coil Packs - Easy to diagnose if its a constant or very frequent miss as you can disconnect the wiring harness to each one (briefly) while running to check if the miss gets worse or stays the same as it was. If the coil pack has been cracked or damaged by water it is unlikely to be too reliable (i've had a few with cracked backs). Also check the spark plug tip to see if it has been firing, if not that could be due to your spark plug or signal getting to it (coil pack, ignition wiring harness etc.). You could always get a spark tester which connects to a short ignition lead off your coil pack and 'jumps' the spark to see how strong it is. A dead coil pack is unlikely to deliver the same spark as a good one.

Spark Plugs - remove each plug one at a time and inspect them together. There are a lot of things you can tell from the condition & colour of this, check out a comparison table on the NGK Website (under tech information i think). If you notice one of the plugs is strangely different to the others then its likely that is the cylinder having trouble - and often its not the spark plug. Make sure you are running NGK Platinum or better as these have been proved time and again to be the best standard plugs to use.

Power Transistor - this can be a tricky one to diagnose. Basically you need to remove it & check continuity (or check for a circuit) between the different combinations of input/output pins. There is a table in the workshop manual which explains what you should try testing with what. Generally I have seen 3 out of 4 power transistors blow on cylinder 2. So if the car is misfiring and you disconnect the wiring harness to the second cylinder coil pack - if the sound doesn't get worse it could be the coil pack or the transistor (spark plug very unlikely).

Air Flow Meter - if this was gone then you would most likely not be able to rev the car past 2000 or 3000rpm. The ECU automatically senses this & does it to prevent further damage. Only worry about this if the above is happening or if the car is constantly running badly rich & you can't get the mixture right. Sometimes they develop a film on them which can be cleaned off with alcohol and a cotton bud (carefully).

[roshfe]

Okay - Heres a bit more info...


Plugs are double spark platinums
ECU reads fine (55)
Engine revs past 3000 rpm okay
Idle is rough and around 500 rpm
ECU shows O2 sensor working fine (LED flashes more the 9 times in 10 secs @ 2000 rpm) as per Chilton manual
Car starts fine but may stall due to rough/low idle. If it does stall, I sometimes have to let it sit for 5-10 mins before it will start (like it is flooded)
recently had to have the Cat replaced. It was pretty much plugged (prob due to rich mix).
Acceleration from a dead stop is crap. Merging with traffic is getting dangerous it is so bad.
Gas mileage has gone WAY down (approx 170-200 km / 25 litres) . . . it was around the 300km mark when I first got it.
All problems got worse when the weather started getting colder
If I let the car sit for a while (5-10 hrs) in the cold, it will start well, idle @ approx 1000rpm and accellerate nicely. about 1 minute after starting to drive, idle drops and accelleration goes away.


Well - that's all that I can think of for now to include. I will check out the coil packs etc as soon as I can get some (half way) decent weather...I wish that I had a garage that I could work on the car in! :rolleyes:

Thanks for the suggestions so far.


RoShFè

[TTriX]

roshfe...
for some reason i am thinking it's in your sending unit/feul pressure...
i would guess to check the top of the sending unit for breaks in the wires...these cars have been known for the wires to break at the pump.
T
you could aways check the pressure with a gauge and see how close it is.

[roshfe]

Thanks TTriX & Lonx:

I sorta had it in the back of my head that it might be Fuel related somehow. What does the sending unit look like and where do I find it? Where / how do I check the pressure?

I assume that I will have to buy a guage of some sort to do the pressure check. What would the gauge be called and approx how many $$$'s to buy one???

Then again, if the pressure is low, how could that result in the flooding and the rich mixture? Maybe I have two problems?

Thx

RoShFè

:crazylook

[Lonx]

To check your fuel pressure you could try plugging the pressure gauge directly after the fuel filter and turning the key to start the fuel pump. Otherwise (and this is the better way) get a T-piece which allows you to plug the pressure gauge inline while still being able to start the car. Make sure its a wet pressure gauge too, I don't think the dry ones like fuel.

Most mechanics should be able to check this in 2 minutes by driving to them though.... and if they have the time they might be able to make better suggestions with the car running in front of them.

Check the connection to your throttle sensor also, these can cause really rough idle problems - but usually the opposite - when the car is cold - however if the car has been tuned with this not working correctly (ECU doesn't always pickup on a bad wire, it didn't with mine recently) then the problem could still stem from there.

Have you tried adjusting the idle screw? Might be worth it just to get the idle to try & sit around 750 - 800rpm. Which might help some of your fuel economy temporarily. Did this problem slowly get worse or did it kind of start one day & just got serious in winter?

[TTriX]

the sending unit is under the back seat...
if you remove the lower part of the back seat you will see an access panel...4-10mm bolts...remove this and you will see the wires that go to the unit...check those just to be sure...
and a fuel pressure guage from "princess auto" in kitchener, ontario, was 20 bux and i am sure it will give you an idea of what is up...if not pm/email me and i am sure we could set somethin up...i have an in-line guage from one of my other pulsie's that you could use.
T
i have a nice heated shop(3 bays) that i could offer(will work for beer-hehe),
but like you know i live about an hour from you...you missed a couple good parties-hehe

[roshfe]

Lonx:

The power (accelleration) issue has been there since I got the car (June2002) but got dramatically worse once it started to get cold. I have had the car into a few mechanics and I believe that they are pretty much usless - they have suggested a few things which I have had done and nothing has made any difference. (New cat, new O2 sensor, thermostat, full tune-up, etc) I will stop by Princess Auto later this week to get a Fuel Pressure Gauge and a T and give it a try.
I have checked the TPS and it is set fine - is the Throttle Sensor something else again? What is this, where is it located, what does it look like, what does it do, etc?
I have also tried playing with (what I think is) the idle adjust screw. I say that I think that it was the right screw cause when I adjusted it, it made no difference to the idle at all. Should I see/hear a difference "real-time" as I adjust it? I would think so. I dunno - maybe I'm tweaking the wrong thing.

TTriX:

I might just take you up on yer offer.
How I would love a heated garage that I could pull the car right into! ( :stoned: jealous). I will try to pull the back seat out and take a look at the sending unit & connections. If I don't hit "pay-dirt" soon, I might be getting in touch... K/W isn't that far away. What kind of beer do you prefer? :guiness:

Thanks again to ya both for the assistance.

RoShFè

[TTriX]

you might just be adjusting the wrong screw as the idle should go up or down...under the throttle spring there is a lip and it rests on a set screw(this is the idle adjuster)...real bitch to turn as the threads face downwards.
as for beverages...i am not picky-hehe ...something that you like is fine as i encourage sharing-hehe. i rarely drink so it makes no difference to me!
as for the tps...it is the throttle position sensor-black box opposite the throttle spring...this just tells the computer when you have applied the excellerator...works like a switch.
Ted
i'll email you and give you my phone number if you have lost it or???

[roshfe]

Hey:

I saw the mechanical "hard stop" that you are refering to but haven't adjusted that.

As per my Chilton's manual, it says to adjust the idle thru the "Idle Air Adjusting" (IAA) unit. This is located on the same casting as the AAC valve on the drivers side of the engine near the firewall. I adjusted the "Idle Adjust Screw" (in both directions) and saw/heard no difference in engine revs.

I may end up adjusting the hard stop just to keep things from stalling as the winter temperatures continues to drop but I still need to find the "root cause" of the problem(s). Then I will have to re-adjust it back down again.