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Pre-Trionic Boost Issues - Pulling my hair out now!!!

1K views 19 replies 6 participants last post by  sleepy3863 
#1 ·
ok, so i have a 92 9000CD Turbo AUTOBOX that ive had for about two years now... i just replaced the DI cassette, because i was losing power in the midrange, idle started to fluctuate... just installed the new one, took for a quick ride... first run, boosted almost like it was no longer in base boost... second run, a little less boost, and third run back to base... ive replaced the APC valve, ive installed new plugs, no brake light issues, all vacuum hoses are in good order, get fuel cut if i disconnect the W hose from the apc, theonly thing i can think of that i havent tried is to disconnect the electrical connection of the APC and go for a run... being that my car is pre-trionic, i have a apc ecu, and a fuel ecu, correct? both are on the drivers side under the aquarium cover... what else could be dropping me back to base boost??? it is an auto, WITH TCS, and i think it has the ETS as well... any help would be greatly appreciated, so that i may still have hair left when this is done...


TIA,
Mel
 
#2 ·
ok, so i have an update... installed new plugs, NGK BCP6RES-11, (the BCP7RES-11 were out of stock EVERYWHERE until thursday) and the boost came back to life!!! for only about five minutes, then went back to base... very upsetting!!! anyone have any ideas for things i can check as to why my APC box is cutting me back to base boost???
 
#3 ·
ok, so i know someone out there has a 9k that is not trionic that has had boost issues, and i am hoping that someone has had similar issues as i have... boosted fine for a few minutes with new plugs, reverted back to base boost after that... i think it has something to do with the APC, but not too sure... the only thing i have left to try is install the old one, and see if that changes anything... i am starting to wonder if the car is lpt or fpt, as i dont remember it ever boosting into the red, minus when i disconnected the hose from the apc and hit fuel cut... is there a part number on the apc box that i could decode somewhere that will say if it is for a lpt or fpt? cruise control works like a dream, will start working just past 25 MPH, brakes work great, all bulbs replaced recently, no lights staying on when they shouldnt,new plugs, new DI, new (used) APC solenoid, same old APC box.... seems to be the only thing left... any ideas anyone??? im willing to try ANYTHING within reason...
 
#4 ·
I thought LPT cars didn't have a boost gauge, or APC units for that matter. I've got a B234R ('98 CSE) and it boosts upto where the red and yellow lines are mixed, but never into the plain red portion of the gauge. I'm not even sure what base/max boost is on my car. Maybe my gauge is off because atmospheric pressure is a good bit into the yellow.


If you're willing to try anything, maybe water injection could help. Short of that, maybe filling up with race fuel and seeing if it holds boost.
 
#5 ·
LPT cars dont have a boost gauge, or an apc, or an intercooler, but im starting to believe that someone was in the process of converting it into an FPT but didnt get as far as changing the APC box... so i guess i have another question... in an automatic FPT 9000, at what rpm range would you start to notice the pickup from the boost? i know when i disconnected the hose from the apc valve, it kicked in around 2600-2800, which was great... but thinking about it, it probably wouldnt kick in till after 32-3300rpms... just a thought...

@Solid Snake:
from what i understand, your car would be a little different, being that you have trionic to control everything.... before there was trionic, there was LH 2.4, and also 2.4.2 (which i have.) there was a separate ecu for the fuel, and a separate ecu for the apc, and an old school chip change(from what i understand) is the only way to get a performance boost, whereas the trionic ecu can be unplugged for ?20? minutes, and relearn the car, with new parts, upgrades, everything... might be wrong about some parts, sure someone will correct me...
 
#6 ·
I thought all DI cars were Trionic. How do you know yours is not? They both use an "apc" valve with the three hoses to control the wastgate. Trionic uses the DI cassette as the knock sensor. APC cars have a knock sensor on the back of the cylinder head between cylinders 2 and 3 and a separate ECU in a gray box usually under the passenger seat. The APC box may be red if it is a hopped up version from the factory.

BTW, those 6 heat range plugs are too hot for your turbo. You need 7 heat range for maximum boost pressure. The 6's will be safe to run but not ideal.

Vacuum leaks are a common cause of base boost issues. The hooter valve and the PCV valve are prime culprits but any vacuum leaks may cause the wastegate to stick open at base boost.
 
#7 ·
i wasnt too clear on the idea of our cars having knock sensors, since everyone states that the DI cassette senses knock... as for the plugs, what do you mean "too hot for your turbo?" are you suggesting that the plugs will burn too hot, resulting in possible pre-detonation, which could pull me back into base boost? thats something that could very well be true, but i did notice when i ran the 7s, the car had a little LESS power, and have changed them after only two thousand miles... the 6s that were installed prior were in for a little more than 6000 miles, and still looked brand new, but i wanted to change them just because i try to keep them down to about 5000 miles between changes until i get everything in the car sorted out, and know what the car likes and doesnt like... upon inspection of the 7s, i did notice that they seemed like they were burnt, like they had overheated, something that i had not noticed before with the 6s, but i will still check them out again with my next change, due to replacing the DI cassette...
 
#8 ·
I have a Sept 1992 2.3 CSE auto myself. It is Pre-Trionic also. I have both Abbott Racing fuel and DI chips fitted. My kickdown boost is about 2500 rpm I think. Does your car kickdown if you floor it about 40 mph? I have 1.5 BAR of boost, but that only shows on the auxiliary gauges, NOT on the car's own gauge. Have you checked the vacuum hose that goes from the plenum chamber through the firewall to the boost gauge? Mine had a little crack in it causing it not to boost up, and was traced to this. Have fitted silicone hose there now.
 
#9 ·
@UK9K:
yes, it does kickdown @40mph, but it only goes mid yellow, at most only to end of yellow where the red starts with the hash marks... the vacuum hose from the plenum to the boost gauge i cant seem to find on mine, do you have a pic you can post of yours for comparison? if mine is different, ill take a pic and post that... is your 9k a CSE? would that make a difference? also, im still trying to find out if there is a way to find out if my car was originally a LPT or FPT car, i know i have the APC valve, the intercooler, and the gauge in teh dash, but im thinking someone was trying to convert it to an FPT if it wasnt already, as the mileage doesnt match the carfax report, but the PO sold it after it was stolen, and the insurance company fixed what was broken...
 
#10 ·
NGK uses a reverse heat range numbering system from that usually used by other manufacturers.Lower numbers are hotter plugs.

On knock controlled boosted engines using hotter plugs tends to induce premature knocking which lowers boost. It rarely causes problems with the plug or the engine, unlike non-detonation controlled engines which can be severely damaged by incorrect heat range plugs.

The 2.0 and 2.3 9000 Turbo engines are designed to use NGK BCPR 7 ES plugs. I have had good luck with platinum 6 heat range ( PHRF 6) plugs. I have actually run BCPR 5ES plugs with no ill effects due to an installation error at my dealership. The engine ran a little flat but no damage occurred to plugs or engine.
 
#12 ·
thanks super for the info, will be changing plugs out as soon as someone stocks them locally...

i ran a few errands this evening, and didnt have the radio on, and noticed that i can heatr the turbo whistling like it is spooling up as i drive, but ive never heard it this well before, under the same circumstances(i.e., radio off, driving around the same time, little to no traffic) and am wondering if i have a leak somewhere, and just havent been able to pinpoint it as of yet... i will try to get it in the air tomorrow at work(with a forklift) just long enough to see if there is anything loose or not connected or cracked(as in the plastic caps on the intercooler, from what i have read they do that quite easily) and will report back with updates...
 
#13 ·
finally got around to checking the intercooler end caps, they seem fine, cant find anything wrong there, all clamps seem tight... i just found a few feet of silicone hose that i had left over from when i redid all the lines on one of my other cars a few years ago laying in a ziploc on a shelf in my garage.... think i will swap that hose in for all the hoses on the car, give it a touch of color under the hood... wonder if that may do anything...

@UK9K:

did you ever get a chance to snap that picture of the hose? am interested to see where it routes to/from
 
#14 ·
I think i'm gradually eliminating issues where I think mine is still running base boost too (half way up the yellow) - have replaced the plenum to Y and Y to firewall hose so far but judging my the state of those two when removed (looked fine at a quick glance) they were perished to hell. Y piece to dump valve tomorrow morning, then if i'm feeling brave i'll look for the "in car" bit to do that as well.

On mine, the gauge never went negative (into the white); now it creeps into it a little, so some improvement! New plugs are also on the cards tomorrow (BCPR7ES), as well as a complete fluid change, new thermostat and filters.
 
#16 ·
thanks for the pics... from memory i dont have a hose coming off the plenum chamber, so when u get off work tonight ill try and snap a couple pics for comparison... havent gotten around to fitting the silicone hoses yet, but its on the list of things to do after i figure out this fuse issue... RH parking lights and instrument lights fuse keeps popping, just replaced all bulbs two weeks ago
 
#18 ·
i changed the bulbs with it hanging on, i did it all outside the parts store where i bought all the bulbs... my uncle said that it is probably under the hood, a wire is pinched going to the front parking lights, and its grounding out... thats a possibility, since i took out the parking light to replace those bulbs, maybe something got in the way when i put it back in... it was almost dark when i did it, so anything is possible
 
#19 ·
Well, if your car was a LPT being converted to a FPT, unless they'd changed the speedo unit you won't have a boost gauge in the car (the Saab gauge above the fuel/temp gauges), and if you don't have that you won't have the hose going from the plenum chamber through the firewall because there's not a gauge on your car for it to go to!
 
#20 ·
thats what im thinking, is that the PO was in the middle of converting it over to a FPT, and then sold it.. is there a way to find out if the APC box is mapped for an LPT or FPT? one would think that a LPT car would be missing the APC box, since there would be no need, it would always run in base boost.. but, who knows, they probably do have them, just mapped that way... are teh part numbers the same from an LPT and an FPT for the APC box?
 
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