Bad Cats, Off timing, Knock Sensor, or what?

[Jeff Williams]

My black 1994 Q45t is quite different from the silver one I have owned, for 2 years. It idles smoothe as glass. It cruises like it is riding on air. It gets about 20 MPG on the highway. The transmission seems to shift wonderfully. If I tip in the throttle a bit, it responds just like the silver one. The BIG difference, is when I punch it. It kinda feels like my boat, with the anchor dragging.

Iwas in the silver one, and Evie was in the black one last night, and we came to a stop light, right by the house. I indicated that I wanted to race, & she oblidged. When the light turned green, i hesitated just abit, to make sure she saw the light change (about .07 seconds), then punched it. The silver one chirped the 255/45/17's and jumped a clear car length on the black one, which just moved out, like a Sunday drive.

I noticed it, while trying to pass a truck, on our trip home. The car does not want to accelerate, at WOT. No black smoke, and the engine was not racing, like a slipping transmission. It just seemed like the timing had retarded.

Anthony had replaced the fuel pump, filter, and controller recently. He replaced the plugs recently, as well. The dealership and his local speed shop had been working on the car for a while, and thought the fuel pump was the fix. He said the car was a real dog, but runs 100% better, since he replaced the fuel pump and controller.

Is it just the California emmissions robbing the car of power?

I am heading to Hilton Head, SC September 4th or 5th, and might just drop it off at T3 in Atlanta, for the week.

Any ideas, or experience with this will be appreciated.

Thanks.

[Q451990]

How clean is the throttle body, runners, plenum, EGR, injectors, etc? My guess would be that it's something in that department. If you're coming through Columbia on your way to HH (not sure how you'll make the trip) let me know! My other guess would be knock sensors...

Heath

[Jeff Williams]

How clean is the throttle body, runners, plenum, EGR, injectors, etc? My guess would be that it's something in that department. If you're coming through Columbia on your way to HH (not sure how you'll make the trip) let me know! My other guess would be knock sensors...

Heath

I thought about the plenum, TB, & EGR, but I think all that was replaced, and cleaned. The plenum looks to have been off, and the throttle body looks to be new. I know that Tony spent a lot of money, chasing the problem, until he replaced the fuel pump and controller. I will review the servcie records tonight, to see when it was done. I might even have time to look in the plenum, to see what condition it is in. I hope it is NOT the knock sensors. I will probably drive the silver car, while I am replacing the suspension pieces, and then drop it off at T3, if they have time to look at it.

I wonder if the ECU and TCU can be swapped for a non-California model, like AZhitman's?

We typically drive east to Atlanta, then on to Savannah, or at least to 95(?), then up North, to Hilton Head.

Thanks for the help.

[psychic_mechanic]

My first guess would be KS. I just ran a tank of regular in my 94 by accident and could really tell the difference, especially flooring it on hills.

[psychic_mechanic]

It just seemed like the timing had retarded.

KS retard timing 4 degrees if I rmemeber Q45Tech's posts accurately.

[Q45tech]

Must do a data log [ zero to 55 mph] to see what the timing, MAF voltage, and injection pulse is at each 100 rpm increment from 4,000 to redline.

Make sure the engine is injesting the right amount of air [Maf voltage] and then the fuel is right and the timing is correct.

Have seen melted preCATS and bad MAF on 94-96.

Who knows what California fuel did to the car?

The CA and 49 state ecu were pretty close by 94.

[Jeff Williams]

Must do a data log [ zero to 55 mph] to see what the timing, MAF voltage, and injection pulse is at each 100 rpm increment from 4,000 to redline.

Make sure the engine is injesting the right amount of air [Maf voltage] and then the fuel is right and the timing is correct.

Have seen melted preCATS and bad MAF on 94-96.

Who knows what California fuel did to the car?

The CA and 49 state ecu were pretty close by 94.

Are you busy, Labor day week? I would like to have T3 look at it, and if you are not too busy, give me your opinion.

The driver's seat/steering wheel memory is screwed up, too. It worked for a few days, and now 1 & 2 just flash, even when the car is off. I have tried a reset, but am not sure if I did it correctly.

I would love to meet you, and show you the car.

[elwesso]

It sounds like KS to me..... As well as timing (which are inter-related)

Get your timing light and see what it reads..... If its at 5*BTDC (which is what I suspect it is), that means its off 5 degrees or so (which is normal for wear, IMHO) and another 10 degrees for the bad knock sensors.....

checked ECU codes??

When I did my plenum I dont think that the intake runners and such had anything do with it... The idle is smooth as glass (little bumpy since I cleaned some better than others, was ready to get the stupid spider back on).....

[Jeff Williams]

It sounds like KS to me..... As well as timing (which are inter-related)

Get your timing light and see what it reads..... If its at 5*BTDC (which is what I suspect it is), that means its off 5 degrees or so (which is normal for wear, IMHO) and another 10 degrees for the bad knock sensors.....

checked ECU codes??

When I did my plenum I dont think that the intake runners and such had anything do with it... The idle is smooth as glass (little bumpy since I cleaned some better than others, was ready to get the stupid spider back on).....

I will put the light on it, tonight, if it is not raining when I get home. Are the instructions on your web site? I don't recall which thread you put them in. I recall it was relatively easy, though.

I may have time to check the ECU for codes, as well.

The car feels great, when I tip in the throttle a little bit. It has great pep, just like the silver one. It will jerk your head back, with a short burst of speed, when I just tap the throttle. It just bogs, when I go WOT, though. Not a hesitation, or transmission slippage, just a "Quadrajet-like" response.

[elwesso]

I know the feeling Jeff, and that sounds kinda like KS to me, as the timing gets retarded a little at WOT...

I posted a thread on the little wire to clamp...... If you need help finding it, call me somtime, 765-621-8336

[Q45tech]

The reduced timing won't show up on a timing light idle test since timing up to 5 >25 degrees is added electronically to the 15 degrees initial amount.

You must data log: rpm vs load vs timing to see if some is missing

Like not having 22 at 4,000 rpm WOT or 26-28 at 6,500.

Cruise light load 60 mph [2000 rpm] might be as high as 40 degrees advance.

[Jeff Williams]

The reduced timing won't show up on a timing light idle test since timing up to 5 >25 degrees is added electronically to the 15 degrees initial amount.

You must data log: rpm vs load vs timing to see if some is missing

Like not having 22 at 4,000 rpm WOT or 26-28 at 6,500.

Cruise light load 60 mph [2000 rpm] might be as high as 40 degrees advance.

Is this what the Consult does, on a road test?

[Q45tech]

The Consult allows you to pick groups [1-20] of parameters and RECORD in 2/100th of second samples for roughly 2 seconds before and 4 seconds after you trigger the record function.

300 readings as you accelerate for every input and output parameter of ecu.

But a bunch of numbers mean nothing without experience and comparable data to evaluate.

[elwesso]

Quote »The reduced timing won't show up on a timing light idle test since timing up to 5 >25 degrees is added electronically to the 15 degrees initial amount.[/quote]With all due respect (and somewhat topic changingness), have you checked the accuracy of METHOD B vs SST..... I am really curious to see how the accuracy compares....

[Q451990]

Jeff,

You're definately on the right track with taking it to T3. It's amazing how much guesswork Dennis and Consult can bypass - you'll save money and a lot of heartache in the process!

Your trip won't take you through Columbia, but I'm very familiar with your route - my girlfriend used to live in Savannah, so I know the drudgery of I-16 from a few Savannah to Atlanta trips. If you get bored with the beach and the two factory outlet malls, just take I-95N to I-26 West... it's a 2.25 hour drive

Heath

[Jeff Williams]

The Consult allows you to pick groups [1-20] of parameters and RECORD in 2/100th of second samples for roughly 2 seconds before and 4 seconds after you trigger the record function.

300 readings as you accelerate for every input and output parameter of ecu.

But a bunch of numbers mean nothing without experience and comparable data to evaluate.

This sounds like an offer to help.

Can I bring it to you?

[Jeff Williams]

I just went through the servcie history on the car.

Interesting read.

The car was purchased from Frontier Infiniti, September 1, 1997. It was an off-lease car, with 45,000 miles on it.

Ground wire added to MAF in November, 1998 at 61,000 miles.

Tony had the injectors replaced in March, 2001. #7 faoled, and he had all 8 replaced. 74,000 miles.

The MAF was replace in September, 2001 at 76,500 miles.

Fuel pump, controller, filter and relay replaced in August, 2003 at 90,000 miles.

Plugs and Fuel Pressure Regulator replaced in September, 2003 at 90,500 miles. I think they are Bosch (I know - I am getting new NGK's tomorrow).

Water Pump, hoses, thermostat, Battery, Brakes, Rocker Cover gaskets, PS lines, etc. in December, 2003 at 92,000 miles.

Regular 3,750 service, 7,500 service, 60,000 service, and 30,000 mile service at 90,000 miles. Synthetic engine and transmission fluids. Brake, PS, and water system flused regularly.

The car seems to be well servcied.

The Knock Sensors gave a code, on the ECU, at 90,000 miles, but were not replaced, because the code did not return. Fuel Pump replacement fixed the problem. The car overheated at 92,000 miles, when the water pump was replaced. Tony did not let the car go very far, when the temp gage went up. He had it towed. The KS's did not code again.

I kind a think it is the plugs AND the Knock sensors.

IF I can get the plugs next week, I can replace them, then, get it to T3, for a consult, and see if Dennis will test drive it.

It's too bad they didn't replace the KS, when they had the plenum off, to replace the fuel regulator.

[elwesso]

Jeff, where you getting your NGK plugs from???

[Jeff Williams]

Some web site, called Q45.org, or something...

Do you have them in stock?

[elwesso]

Oh yeah, Ive herad of that.. Theres this crazy asian out there now who thinks he can do anything, and is writing all these cool writeups!

Jeff, shoot me an email [email protected] and ill fill you in with all the details...

[Jeff Williams]

You've got email.

Has anyone tried the Iridium plugs?

[Q45tech]

Why, the platnium last 60k and changing the plugs often is the key not finding something that prolongs the interval and avoids your looking in the plug well for rtv failure [oil soaking].

No plug will add hp only the chance to decrease it.Jeff:I will be out of town Sat4, Sun5, Monday6 LD weekend.......check with T3 they probably will close Monday.

[Jeff Williams]

Thanks, D. I always like trying something new. Just saw them, and had absolutely NO info on them. They seemed to be the same cost, as the std plugs.

I guess dropping if off, for the week, wouldn't be a good idea, then. I'd really love to have your and T3's opinion of the car, and have it tested for needed repairs.

I have the report from the shop in Cali, and it listed the PS pump & hoses, PS Rack, struts, boots, upper links, etc. I ma more concerned with the engine and mechanical aspects of the car.

I can handle the suspension (have the parts on order), and will hold out on the steering leaks, for after I detail the engine, and determine where the leaks may actually be. I saw that Tony had replaced some of the PS hoses.

[duck3986]

Jeff,

Any luck resolving this issue?

Don