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Discussion Starter #1
Hello SAABers,
I have a 1991 model 900T 5 speed 5 door, converted to T5 with a T7 APC valve. When I bought the car it was overboosting and cutting fuel on more than about 2/3 throttle. I bought a new T7 APC valve and had this fitted. Initially it seemed a bit calmer, but would still overboost on heavier throttle settings. When starting up and idling, this T7 would be clicking away like crazy, which I never noticed with the old valve. I stored the car for 10 months, with monthly startups, letting it get up to temp. When I put it back on the road, which coincided with replacement of the brake booster since the old master cylinder seal had gone and was leaking brake fluid into the booster, which also had a perforated diaphragm, I only had base boost. Well I'm assuming this is what's going on. Under full throttle in 3rd up a hill, the boost guage swings to around 2/3 through the yellow and sits there. It used to go right into the red.The T7 doesn't make any clicking noises now. I initially put this down to the new brake booster helping keep the intake system sealed/pressurised, but I want some more boost back!

Today, I fired it up and touched the harness connector on the T7. It immediately started clicking away, but stops again after I stop fiddling with the connector. There's also another single wire feeding into the loom that has a connector, this is cable tied to the loom that connects to the T7. I didn't have much time, but couldn't see any issues with either connector. I didn't know how to remove the connector from the T7. Help! How can I get this going properly guys?
 

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T7 valve should click, because it have only 1 coil and spring (to close).
T5 valve has 2 coils and no spring.
 

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It's not really possible for us to tell you what wires go where, since the wiring harness is custom made. You can use a multimeter to trace any given wire back to its position at the T5 ECM, which will tell you what that wire is supposed to be doing, what it's supposed to be connected to.

Similarly, we can't really tell you what the ECM is supposed to be doing without knowing what sort of tune it's running - maybe you have a stock 185hp tune, maybe something else. The tune will define what boost you're supposed to be getting. It might be worth investing in the hardware to run t5suite so you can make that determination in a concrete way. t5suite data logging might also help you determine whether boost is being limited by a malfunction (bad wiring, valve, knock, etc.) or whether it's being limited by the tune.
 

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Discussion Starter #4
Thanks guys!

So, should a correctly operating T7 be clicking away like crazy at idle speed, no throttle? I wouldn't think so. It's a very new valve.
I'm tempted to say my car is running the T5 kit from Europarts, or at least the loom looks very professionally made, with the T5 ECU installed behind the right side kicker panel. Only Ed Graetz could answer that, since he built this conversion. Does Ed still frequent this forum?

The tune it's running was described to me by Ed as 165kW 320Nm, 20psi boost. It's been complaining about coolant temp sensor since I bought the car, and probably flashing other issues too. Now I know you're going to ask me to count the flashes, so I'm going outside to do that right now. I'll be back before you know it. OK, error codes 4 and 7.
 

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Discussion Starter #5
I found these Check Engine Light (CEL) codes on UKSAABS forum:
2 Manifold absolute pressure sensor P0105 P0106 P0107 P0108
3 Intake air temperature sensor P0110 P0112 P0113
4 Coolant temperature sensor P0115 P0117 P0118
5 Throttle position sensor P0120 P0121 P0122 P0123
6 Lambda (oxygen) sensor P0130
7 Fuel-air mixture P0170 P0171 P0172
8 EVAP valve (ELCD) P0443 P1443 P1444 P1445
9 Internal ECU fault P1651 P1652 (check ground, connectors)


P0170 Fuel Trim Malfunction (Bank 1)
P0171 System Too Lean (Bank 1)
P0172 System Too Rich (Bank 1)

Do these look correct for T5? Do you have to have the T5 Suite and cable connector to see which of the several P errors is being thrown for each number of CEL flashes? Perhaps I'm out of my depth here, but I'm willing to learn.
 

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What ECM are you running? I think flash codes are limited to the '93-'95 ECMs that are pre-OBDII - the P-codes you indicate above are for '96+ OBDII ECMs. Different animals. I would be shocked if someone used the old T5 ECM on a conversion when the new box is simply better, but people do weird stuff. For the earlier boxes, you need to have the old-style diagnostic connector wired to display the codes via CEL. For the later boxes, you need to have a J1962 OBDII connected wired up and an appropriate OBDII code reader.
 

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To add: I'm pretty sure under all circumstances a flashing CEL means catalyst damaging misfire. I don't think the old box will "volunteer" flash codes... they must be manually triggered. The new box definitely will not.
 

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Discussion Starter #8 (Edited)
Thanks Jvanabra, but I was told the Check Engine Light on the dash lights up solid while driving if it has any errors. To see which errors, you turn on the ignition without starting the motor, and count the flashes. The CEL on my car currently flashes 4 times, pauses, then flashes 7 times, then it pauses for longer, before repeating this process. It will do this as long as the ignition is on with the motor not running. How would I tell from a visual inspection which ECM my car has?
 

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If it's flashing codes, it's the early version. The late version does not do that - it requires an OBDII code reader. Pretty sure all early T5 ECMs share the same logic, so codes for you are:


Looks like 4 and 7 are "coolant temp sensor" and "fuel:air mixture."

To erase them, you need to have the diagnostic socket wired up and a Tech 2. You can prevent them from displaying by disconnecting the battery for a few minutes, but they'll remain stored in memory until cleared by Tech 2.
 
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