This was originally here:
https://www.thirdgen.org/techbb2/sho...threadid=73661
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First off I hope I don't chase anyone away by starting out saying I have a 91 Caprice 9C1 (ex police car) that started out life with a L05 350 which is why I'm posting here. It's so similar to what a lot of you guys are running. The new motor is all in the car and running but not very well. Here's a parts list:

- Replacement Caprice TBI 350 crate motor (minus the standard heads and cam...which are for sale if anyone is interested)
- Vortec heads
- Vortec TBI intake (from GMPP)
- LT4 (not hot) production cam
- Vortec exhaust manifolds with external EGR
- reman. HEI distributor, new cap, rotor, coil, wires, plugs
- stock TBI with 65#( I think...) injectors but with the vacuum adjustable fuel pressure regulator using the spring that came in it....didn't swap in the one from the original fpr.
- complete stock dual exhaust setup from an LT1 Caprice (true duals, 2 cats, 2 mufflers, 2 resonators, no crossover in case you were wondering)
- I have the most current version ECM in the car but that is stock as well.

I didn't do the work, I had a mechanic do the install/assembly.
It starts up ok, idles ok, temps don't get too hot and oil pressure is steady and good.

Here are the issues:
#1 - The engine is making a noise after it gets nice and warmed up. It starts out real quiet and gradually gets louder and louder till the engine is completely warmed up. I doubt anyone will know what this is just from this description but what the heck its worth a try. It appears to be vaccuum/pressure related in some way becuase as it first starts to come in accelerating or even braking (I assume drawing vaccuum for the booster) will make it stop, but once its fully warmed up only decent 1/2-full throttle acceleration will make it completely quiet down. The sound is fairly high pitched and pulses. Tone and volume does vary a bit with RPM. I have access to a digital camera that can take mpeg movies and will be recording the sound and posting it within a few days hopefully.

ADDED - Ok...I have second opinion on this. Since I was outside messing around with it. Wouldn't call it whistling now (sounds a lot diff outside the car than in with the windows up). The best description is a bearing noise that varies with RPM. But the thing that gets me is that (once it's all warmed up and does it all the time...) if I turn the car off the noise kinda peters out in a matter of like 2-3 seconds. It doesn't stop immediately with the engine and kind of wheezes to a stop. At that point it sounds like air. When I start the engine after that, it takes about 4-6 seconds for the noise to start and it quickly (<= 1 sec) raises in volume to full at that point.

#2 - As mentioned at the start, the power really isn't there like I was expecting and it doesn't really run that good past 1/2 throttle. It has even backfired a couple times.

#3 (related to #2 I'm sure) - If I use 3/4-full throttle it will light up the SES light and set a code 53 (I think that's the right #) which is for ESC, electronic spark control (too much knock/ping), on this car and the car loses all power (It did this while doing 75 on the GSP in NJ and I just gradually slowed to like 40...it wasn't pretty. Removed he ECM fuse for a couple mins to reset the code and drive the car home.) The mechanic replaced the knock sensor and the knock module as well as the the newer ECM which specifically addressed a knock issue. Mechanic has told me he set the timing to 0 degrees at TDC with the ESC connector unplugged as per the Factory Service Manual.

#4 - Mechanic mentioned to me about the spark plug gap possibly being something like .10 too large. How bad, if at all, is that for engine and how much would/could that affect performance or any of the other issues.

I am thinking the car probably needs a custom PROM burned and I am planning on using Ed Wright ($350 ish) unless I hear otherwise (hint, hint). I know this would help out the performance and general driveability and don't think it would have any effect on the knock/ping issue, but wanted any opinions on that. He has spent 2 and half months up to this point doing the work and this was my daily driver. Any reccommendations/suggestions please feel free to post and/or contact me directly (email should be public as well as AOL IM name).

Oh yeah...also, what would be a good handheld scanner unit/laptop+software to get that would allow me to see what's going on in the ECM? I've heard about TurboLink meant for Grand Nationals but works for my car.

 

#1 sounds like the iac valve partially open and when it opens the rpms would rise and when it closes the rpms would fall, but you kinda lost me witht he part you added with it still goes when the car is turned off,

#2 sounds lean, or base timing

#3 dont lean cause pinging with would set the knock sensor off?

#4 dont know about how much .1 would do but i know its fairly imprortant to get the gap right.

winaldl!!! free and i am going to work on that this weekend and get that running for my car

aol im= firbirdgta

 

first off, all tbi'ers are welcome here.
1. it does soudns like either the IAC isn't seating fully or you have a nick in a throttle blade. both can cause a whistle. the IAC is the most likely cause.
2. tiem to raise the fuel pressure and work on a fuel map with a new chip. also you willl need to run a lot more initial, advance and total timing to make power all the way throguh the power band. it is prom time
3. this is caused by the lean out of #2 adn the timing issues. you prolly have just enough fuel to get a little bit of ignition, but then it keeps burning out the exhaust valve, that causes a ton of knock.
4. the gap of a spark plug is related to the amount of energy in the spark. if you have a hot coil and a good ignition box you can open up the gap a bit, if you are runnign staock stuff it is likely that it cna barely handle the factory spec gap.

later
tim

 

I don't know why no one else didn't think of it but the noise could be comming from a spun muffler bearing. Thats why it takes awhile to stop after shut down and a little longer after start up. J/K

Hope you figuer out what the rewal problems is soon, I know how it fills to have your car run bad and not be able to find the problem or problems.

Steve

 

Thanks guys. The mechanic took the car back this past Sunday and hasn't gotten back to me about the noise. Everyone keeps suggesting a lean condition as the source of the code 43. Maybe that is the case with my stock injectors (I think they are like 65#), but I'm using the vacuum adjustable fuel pressure regulator with the spring that came in it, so at WOT there should be 18-20 psi going to the injectors. I'm lost, heh. He mentioned that he didn't degree the cam and just installed it straight in (with the dots lined up??), and the timing is set to 0 degrees with the ESC connector unplugged as per the FSM. It's wierd.

Oh and firbird, I checked into winaldl and my ECM isn't listed on the supported list (89-90 Caprices with L05 are though...figures). The author said to just give it a try it might work or log some data and send it to him and he could probably get the ECM to work in the program .

Thanks again,
Dave

 

I noticed that your stock TBI heads were for sale. How much? i don't have a lot of money, and I'm sure shipping would be a pain to MN, but let me know what you were thinking for a price.

nate

 

lol sorry forgot about that just so use to just thirdgens having tbi and a Occasional van hope we can help figure out your problem!

 

Nate, I really have no idea what they are worth, so if you know or don't just make an offer (probabaly a good time to email me...I doubt you guys like the for-sale stuff in the tech forums). They are brand new heads though. As soon as the crate engine came in he pulled the heads and cam and put on the new pieces. They are currently sitting in the back seat of the car in the boxes that the vortec heads came in. And yes, shipping probably would be a bitch. I'll be going away this weekend so if you do email me and don't hear from me don't worry, I'll get back to you on Sunday.

firbird, it's a valid assumption this being a thirdgen board

Dave

 

Hey, man, I've had some of the same probs after my swap:

Dude, if you're running the stock spring, you are WAAY too rich. DO you have a fuel pressure guage? If not, get one. YOU NEED A FP GUAGE!!! I emphasize need, especially once you start doing mods to your car and once you program chips and have that FPR. Check your fuel pressure after you hook up a gauge, and if it is petering, look into a new fuel pump. This may explain your engine knock. Are you overheating at all? You probably won't notice in NJ in the winter, but once spring rolls around you may overheat, which can be caused by running lean.

As for the noise, check the exhaust. If it is new, you may need to re-tighten the bolts holding it together. My Y-pipe came loose after a couple a weeks, and it rattled pretty loud. If your exhaust is old, it may have rattled loose due to the torque of the new engine. In any, case have it checked. An exhaust shop should be able to check it if you can't get a good view of everything under the cop car. Good luck, man! If you have any questions, feel free to ask, even if you do drive a cop car!

 

Im not sure about this, but could the small combustion chambers of the vortecs in addition to your flat top 350 pistons be causing the pinging? If Im not mistaken, which I may be, your head swap would cause your CR to be fairly high. High enough that you should probably be using premium fuel. If you are using the 87 stuff, I would try the 93 and see if this helps some of your pinging problems.

 

I asked the mechanic to install a FP guage in the beginning and he hasn't gotten around to it, but I'm forwarding him the suggestions here so hopefully he'll wise up and install a guage for me. I 110% agree with JRoy91RS that a FP guage is needed after these kinds of modifications and hope he will install one very soon.
Does anyone know where I could get a cable that would work with winaldl? I don't have a soldering iron and don't really want to make one myself even if I did so if maybe someone else makes em or there's a place I can buy one pre-made LMK. I have no idea if the program will work, but it sure can't hurt to try at this point and I'm sure it would really help diagnose some of the problems. The mechanic has a scan-tool, but I have no idea how much/little info it tells him. I don't know if winaldl would help him out any or just give me a reference for programming later.

Thanks for the replies guys!
Dave

 

If anything, the Vortec heads would probably lower compression on that engine. The pinging is probably due to a lean condition/too much advance timing. After you get a FP gauge hooked up, have your mechanic hook up your car to a scan tool and check TPS, IAC, and BLM counts to make sure the y are within spec. You should also get a Air/fuel ratio reading. WinALDL, from what I understand, is pretty much a scan tool on steriods. All the basic info. you need to tune your car can come from a decent scan tool.

 

Whew...well a couple weeks back the mechanic found out what was making the absolutely horrible noise in the engine and it was......drum roll please....the PCV system wasn't set up right. Usually on a car like mine there is on PCV valve in the left valve cover and it's piped into the front of the throttle body. Then there is a breather in the right valve cover that is piped into the back of the airbox (filtered air). My car had a PCV valve in each valve cover and both piped into a T into the front of the throttle body. Apparently this was causeing an extreme vacuum condition in the crankcase and was sucking in air through a seal somewhere. Supposedly the rest of the issues were taken care of as well (no more SES light and he went back to the proper spark plugs).
It's been a loooong wait for me but I'm hoping in some small way it will be worth it. Now I need a chip burned I'm sure. WINALDL doesn't "officially" support my car but I'm going to try and get a cable and try out the software anyway....it's free, what do I have to lose?
Along those lines I still never got a fuel pressue guage so I was wondering if anyone can reccommend anything. I'd like an electronic sender model so there isn't any gas line plumbed into the interior of the car (becuase I want to mount it inside the car...). Or should I just call up Jegs/Summit and they'll hook me up?
Anyway...thanks for the suggestions.

Dave
91 Caprice 9c1

 

Dave Summit can hook you up with a guage I have several Autometer units but I deceided on a Nordskog unit that looks almost the same an works great. It was cheaper than the $180 autometer unit.