pinking (knocking)

[Si]

If you just took the dizzy cap off and then pressurised the vac capsul would you see the rota arm move back or forth? Maybe an easier way to check it than with a timing light and all the gubins.

[Tomarse]

the rotor arm doesnt move, its bits underneath it that do. If you remove the dust shield you can see them moving.
On the 99t dissy there are 4 contacts that turn with the rotor arm. there are also 4 contacts in the base plate in the dissy. when the vac acvance/retard moves it moves these contacts effectively changing the timing.

[Dean O]

mmm, ain't had a timing gun for nearly 30 years
it goes like a rocket for the 1st 5 mins so wouldn't that rule out a dodgy diaphragm? I think its an unlikely solution because I'd already swapped distributors in trying to cure what turned out to be a jammed turbo, & there was no discernible difference in running between the two. I'm going to replace all the vac lines after reswapping the dizzy.

[Si]

What about the vac line to the warm up reg, is that OK? Is it fed on a single line (nothing else t'd in on with it) from the intake manifold plenum throttle body end?

[RoccoH]

sounds to me like a fuel pressure problem...

[Orca]

Rocco is certainly right with one thing ... troubleshooting the CIS system is almost impossible, if not pointless, without getting a handle on the fuel pressure.

[Jim Mesthene]

Originally Posted by Dean O

when I turn on the ignition, the pump 'priming' noise or is it the relay buzzing for a few seconds? whatever the noise is, it only happens maybe 50% of the time now, whereas I'm fairly sure it always used to be 100%.

Is it a Lambda car?

[Dean O]

no lamda, Jim. (he says peering from behind the sofa incase he's wrong again!) B201 turbo K Jetronic, no cat. I'm assuming a lamda sensor is the one which is attached to an exhaust downpipe? if so, I definitely don't have one
I'm on the look out for a fuel pump now - can anyone give me a part number for a 1989 T8 Special.
and could a blocked fuel filter or a dodgy relay immitate a failing pump?

[Tomarse]

Im hoping to borrow si's pressure tester over the next couple of days and test mine. since i had the same symptoms then its likely we have the same problem.

there isnt mush other than the pump it could really be though i suppose.

I'd also be intersted in the proper number for a T8 fuel pump (as mine is the same!) i have 3 different bosch part numbers on the ones i have! and havent got access to an EPC at the mo.

Sonnett1 has recommended here, as he says they were resonably priced - though you will have to find a local agent for them. Will have to compare them to the prices for the place that you found once we have the right part number!

[Dean O]

I'm hoping its the cheaper one! although I don't mind you snapping it up on the cheap - & me paying more for following your lead & saving me diagnosis costs instead there's also an 8v one on ebay but I can't cross match the bosch & saab numbers.

its new 'old stock' genuine Saab pump part no.7526163 & its going for £49.99
bet it won't be the correct one tho
I'd have phoned the garage to ask but I'm at work 8 - 5 & saturday mornings

ps looks like that catalogue only covers the GM900.

[Dean O]

sorry it wasn't yer pump, Tom
mine'll only start from cold with the cold start plug off & even then only on a couple of cylinders for the 1st few minutes. today it started in the usual manner, drove impeccably for 30 miles, parked it up for 2 hours in the sunshine then wouldn't start at all. had to call the nice people from Green Flag to assist. needless to say it fired up at his 1st attempt albeit on a couple of pots again. then it misfired below 2000rpm all the way home.
his verdict? "its overfuelling" . . . . . "or it could be underfuelling"
Gis a job, I could say that

[Tomarse]

dean - im still messing with mine. give me till midday tommorow and if i still havent solved it i will be ready to give in..

after reading this
my money is now on your warm up reg too. apparently it is possible to sort the problem by rearranging the guts using brute force to set the control pressure to the right value, and there are 2 bits to move to vary both warm up and running once warm.
You need a pressure gauge to set it with but between me and Si we almost have that sorted i think.

[Dean O]

I've just swapped the thermo time switch (already swapped CSI). still no change so I guess the WUR is about all that's left.
still can't understand why it only starts with the CSI disconnected (indicating too rich) but pinks on mid boost possibly suggesting too lean
I'm beginning to think the poor starting & low boost are two separate issues.

[Tomarse]

right Dean, as i said in my thread mine is all fixed now after swapping the warm up reg

I havent fitted a new one (yet). the one i fitted i stripped down and cleaned using brake cleaner and blasting it through with an air line.
if you follow the instructions in the pdf i linked earlier you can take the reg apart and remove the metal diaphram and then clean it all out. you only need a screwdriver and an 11mm spanner to do it (and an airline helps to blast the crud out!).

You could probably swap the warm up reg over yourself. to swap it there is only 2 14mm fuel lines and 2 allen headed cap screws (or cross-heads) holding the WUR to the block.

i am going to enquire about the cost of a new WUR. If you want one im happy to test it for you first! (since i have a proper air/fuel gauge fitted in my car!) if you want to do a thurough job.
with Si's approval i can also post you his gauge with all the fittings you need to check your control pressure. its a bit fiddly to use though due to a lack of the right bits of pipe so you currently have to remove the WUR before fitting the gauge to it and put up with a slight leak from it where you cant quite get in to tighten it.


a blocked WUR also causes hard starting - if the pressure in the control circuit is too high (as happens when the WUR gets blocked) then whole system will run too lean and will not do any cold enrichment.
my control pressure was over 5 bar before. it is now 3.5 max and 1ish when cold. the higher it gets the leaner the system runs.

[Dean O]

thanks Tom

I think seeing as you & Si's gauge have effectively done the diagnosis for me, I'll just swap over my spare WUR. I was going to ask the mechanic to do it, but I'm feeling a bit braver after swapping the TTS. my spare's still attached to the thermostat housing etc so it might be easier to swap the whole gubbins.

[Tomarse]

it really is just 2 screws/allen bolts that hold the warm up reg onto the 'stat housing, and the 2 fuel pipes.

before you fit the spare one, spray some brake/carb cleaner through it and check that you can blow through it (blow an air line thorough it if you can).

the 'in' side is the one with a metal gauze filter, so you probably want to blow it back through from the other side to loosen any crud that is stuck in it, and then blow through it the proper way too. the brake/carb cleaner will probably help too.

[Jim Mesthene]

Why not just use the adjuster on the airflow sensor plate to make it very rich; at least long enough to take it for a drive and see if you get the boost you're looking for? If that fixes it, then you could play with pressures, injectors etc.

[Tomarse]

i tried that on mine. if i made it as rich at idle as the car could cope with it still ran out of fuel by around about base boost.
if the control pressure is too high it just damps the movement of the fuel plunger so much that it cant get the fuel through whatever you do.

[Jim Mesthene]

I agree that pressures are critical. That's why I don't understand diagnoses without a pressure gauge (I haven't heard anyone mention numbers for line pressure and control pressure). You can always set up a temporary switch to fire the cold-start injector to test your theory that lean running is causing the knocking. I suspect that running that lean and knocking that much would have holed a piston by now.
A proper diagnosis of a CIS system cannot be done without a CIS pressure test. Adjustng the pressures without a gauge could only work through blind luck.

[nutcase]

Originally Posted by Jim Mesthene

I agree that pressures are critical. That's why I don't understand diagnoses without a pressure gauge (I haven't heard anyone mention numbers for line pressure and control pressure). You can always set up a temporary switch to fire the cold-start injector to test your theory that lean running is causing the knocking. I suspect that running that lean and knocking that much would have holed a piston by now.
A proper diagnosis of a CIS system cannot be done without a CIS pressure test. Adjustng the pressures without a gauge could only work through blind luck.

See Tom's thread on what fuel pump for pressures for a 1980 99T.

The fuel pressure regulator should never need to be adjusted. It might need repairing at some point but that's it. Tje WUR which does the control pressure could well need tweaking back into life or replacement.