no start problem, only sparks 1/3 CAS rotations
#1
no start problem, only sparks 1/3 CAS rotations
ok so im working on this FC that will not start or run. it has TII ecu, N/A harness (with the 3 wires cut to convert it to TII, including knock sensor addition), S4 N/A block. i unplug the CAS and spin it by hand, and the leading coil only sparks once every 3 rotations of the CAS, as does the injecotrs. Ive tried it on my brothers running FC, and it sparks a lot more often, seems to be about 4 spark/injector events every rotation.
Ive tried several different CAS, two different ECUs, and they all do the same thing. Ive checked continuity between ECU and the CAS and leading coil and its all good. im stumped?
Ive tried several different CAS, two different ECUs, and they all do the same thing. Ive checked continuity between ECU and the CAS and leading coil and its all good. im stumped?
#2
smooth operator
Join Date: Mar 2012
Location: Oakland Michigan
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sounds like you should grab an old plug and have some ank car as you watch for spark one at a time. pull the return fuel line, crank, and check for fuel, make sure you re stab the cas right. check fo 1k olms resistance between the green and black wire on the tps. 1 rotation the leading fires 6 times and the trailing 3.
if you have already replaced the cas with a different one and you have fuel and good timing tps try replacing the coil pack with a spare. i case you have not tried pull the egi fuse, if non of that works torch the plugs and try to start it
if you have already replaced the cas with a different one and you have fuel and good timing tps try replacing the coil pack with a spare. i case you have not tried pull the egi fuse, if non of that works torch the plugs and try to start it
#3
Trunk Ornament
iTrader: (11)
I started writing something probably 4 or 5 times, then realized I had ran into this exact same situation with another car. Check +12v and ground AT the ECU. Clean up all grounds, and do a voltage drop from each ground pin on the ECU to a good known ground on the chassis. If you're getting a voltage from an ECU ground wire to a real ground, then there's a high resistance connection somewhere along the ECU ground wire.
#4
ive checked all the grounds.. they are all about 0.0-0.3 ohms at the ECU connectors. We have had 3-4 experienced rotary mechanics look at this car and we are all stumped. We have tried the following..
Checked all grounds
Checked for 12V at coil and ECU
tried 3 different CAS
tried 3 different ECU's
tried a different leading coil
tried 2 different engine harnesses
re-ran the shielded CAS cable, bypassing the harness
they all result in the same thing, it will spark only 1x per 3 rotations of the CAS. The thing is, it seems like an ECU problem, becuase not only does it spark only once, but you can hear the injectors firing also, so it cant be related to just the coils or coil harness
Checked all grounds
Checked for 12V at coil and ECU
tried 3 different CAS
tried 3 different ECU's
tried a different leading coil
tried 2 different engine harnesses
re-ran the shielded CAS cable, bypassing the harness
they all result in the same thing, it will spark only 1x per 3 rotations of the CAS. The thing is, it seems like an ECU problem, becuase not only does it spark only once, but you can hear the injectors firing also, so it cant be related to just the coils or coil harness
#5
Boost please
iTrader: (7)
Bump this is my car we are having issues with heres the story i got an S4 TII as a project spent months figuring out why it was tying to start so hard. So i ended up pulling the motor out and swapping in an NA stage 2 street port and i have swapped the TII harness with an S4 NA harness now also installed a new starter, new plugs, new plug wires these are the only things i have changed since the TII swap. We have checked all the ground and the continuity and everything checks out. The weird thing is we didnt have a spark issue with the TII motor we have swapped 3 different ecu's, swapped 3 different CAS, 3 different sets of plugs and we have the same issue I have had the best rotary people in SC look at this thing and we have no clue someone please help
#6
pissin' on pistons
iTrader: (26)
Bump this is my car we are having issues with heres the story i got an S4 TII as a project spent months figuring out why it was tying to start so hard. So i ended up pulling the motor out and swapping in an NA stage 2 street port and i have swapped the TII harness with an S4 NA harness now also installed a new starter, new plugs, new plug wires these are the only things i have changed since the TII swap. We have checked all the ground and the continuity and everything checks out. The weird thing is we didnt have a spark issue with the TII motor we have swapped 3 different ecu's, swapped 3 different CAS, 3 different sets of plugs and we have the same issue I have had the best rotary people in SC look at this thing and we have no clue someone please help
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#9
Trunk Ornament
iTrader: (11)
If you don't have this fixed in 2 weeks, I may head up to take a look for myself. From what I can remember on the stock system (I now run a standalone), there are 2 signals from the CAS. One gives a pulse to the ECU 24 times (IIRC) every rotation, and the other signal is twice per rotation. There is one signal that just tells the ECU how fast the engine is spinning, and the other is a reference. It uses the 2 toothed signal to toggle the trailing coils, but fires the leading coil is wasted spark, so it fires both spark plugs 2x per rotation.
I'll have to think more about this issue and get back to you....
I'll have to think more about this issue and get back to you....
#11
Trunk Ornament
iTrader: (11)
It's more than likely an issue with the wiring. If you have a set of coils, ecu, and CAS from a running car, it should be running by now. Inter-connecting wiring is probably the issue. Did you check the insulation resistance of the 4 CAS wires to ground, or even together to see if they're pinched and shorted out somewhere?
#17
Yes, i checked using the connector pinouts in the FSM. there is not much difference between N/A and turbo as far as ECU pinout, and no difference as far as coil outputs and CAS inputs
edit here are the differences..
Pin Function
1R power steering switch (NA), Knock control (Turbo)
2K split air solenoid (NA), twin scroll solenoid (Turbo)
3D A/T inhibitor switch (NA), fuel pump resistor relay (Turbo)
edit here are the differences..
Pin Function
1R power steering switch (NA), Knock control (Turbo)
2K split air solenoid (NA), twin scroll solenoid (Turbo)
3D A/T inhibitor switch (NA), fuel pump resistor relay (Turbo)
#19
Trunk Ornament
iTrader: (11)
I doubt you need to pull the dash out. There's really no reason for that. I know there's really a small difference between the NA and TII harnesses other than the extended/shortened wires here and there, and the 3 pins. I did this myself about 3 years ago, but ended up going complete standalone. The only reason I ask if you've ohmed them each to ground (input from CAS and outputs) and also wire-to-wire, is because I've seen it stump many people before.
Looking back, I didn't see anything about changing out the coils. They have the ignitors attached to them....
Looking back, I didn't see anything about changing out the coils. They have the ignitors attached to them....
#22
Gone Darkside
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AGreen,
I was part of the "party" on Saturday.
I ran the meter to each CAS wire individually on each end to verify they were in the going to the correct ECU pins. No issues found.
We also pulled the CAS from one of the cars that had been driven to his house to verify that we were dealing with a working CAS. No change.
As previously noted, we ran individual wires (shielded) from the CAS to the ECU. No change.
The car was hooked up to a battery charger/jump unit that was putting out a LOT of amps. I'm not sure if that could cause any amount of interference in any way. The battery is relocated to the rear hatch area, but I can't speak for the quality of the relocation.
The only oddity is that I noticed near the end of the day that I would occasionally see a faster bump on the tach. Instead of being a bump every couple of seconds, it would show one per second (roughly). Subsequent attempts would vary between these two variations.
I was part of the "party" on Saturday.
I ran the meter to each CAS wire individually on each end to verify they were in the going to the correct ECU pins. No issues found.
We also pulled the CAS from one of the cars that had been driven to his house to verify that we were dealing with a working CAS. No change.
As previously noted, we ran individual wires (shielded) from the CAS to the ECU. No change.
The car was hooked up to a battery charger/jump unit that was putting out a LOT of amps. I'm not sure if that could cause any amount of interference in any way. The battery is relocated to the rear hatch area, but I can't speak for the quality of the relocation.
The only oddity is that I noticed near the end of the day that I would occasionally see a faster bump on the tach. Instead of being a bump every couple of seconds, it would show one per second (roughly). Subsequent attempts would vary between these two variations.
#24
Boost please
iTrader: (7)
Yeah cursed is right..... I don't really want to throw down q lot of cash for a stand alone unless someone can get me a really good deal on one but this FC is a pain 4 of the best rotor mechanics in SC can't figure it out so I doubt anyone else could unless its some off the wall shizz