2seater
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Posts posted by 2seater
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2 minutes ago, darwin-t said:
I took it off and tested it with an ohm meter.
This was whet I got when it was installedTPS is 0.78 at idle, increases smoothly to 3.20 at full throttle
I figured that was the reading from a VOM, and voltage probably could be calculated, but not how it is normally done. I saw the previous reading and that is well outside the normal range. Is it possible something is limiting throttle travel? A little odd to be high voltage on the bottom and low voltage at the top.
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I don't understand the resistance readings for a tps. It is normally installed and the reading in diagnostics is in volts. The input from the ECM is nominally 5.0vdc and the TPS is a potentiometer. If you look at the TPS, the mounting holes are slotted so it can be rotated in place for adjustment.
The cam sensor code is most often the missing magnet. You need to remove the sensor and rotate the engine by hand until the magnet holder is visible in the hole.
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Yes, the TPS location is rather difficult, and the screws are non magnetic like the others. Always place a rag or something else underneath to keep them from disappearing. I use a dual ended bent screwdriver or a tiny ratchet designed to hold 1/4 hex screwdriver tips.
The coolant tubes on the underside of the throttle both insert into the lower part of the throttle body and seal via O-rings. The outer one, which is visible, is bolted to the intake manifold base. That must be unbolted and loosened from the manifold face and then the T/B should pull off the hidden tube with a pull and twist if everything goes well. Thirty odd years of possible rust/corrosion may resist a bit.
I would verify spark and fuel before taking this apart.
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I agree with the above. When you start to get problems that seem to dance around from one area to another, and don't set a code, you need to look at the absolutely most important item and that is ignition. Nothing else matters. If you verify spark, try a spray of starting fluid into the intake to see if it will fire
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The tps voltage is well out of specification. It should be .38-.42 volts at closed throttle and well over 4.0 volts at full throttle. A high tps at closed throttle can cause a high idle. I suspect the tps needs to be replaced and adjusted properly. The tps acts a bit like the accelerator pump on a carburetor. It doesn’t inject fuel but it tells the ECM what the throttle is doing instantly
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What is your TPS reading at idle and does it increase smoothly with throttle input? Engine doesn’t need to be running to check.
What is your actual fuel pressure, key on engine off, and when running at idle. Second part; does pressure increase as you blip the throttle?
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That puddle at least gives us an idea that it is in the front, unless it is at the rear as well? Aside from the intake manifold possibly leaking, there is also the thermostat although they have a pretty good record of staying dry. It would be best if you can sop up the liquid as much as possible to see if you can better localize the leak. That said, intake manifold coolant leaks are not uncommon and are usually from galvanic corrosion of the intake manifold.
The coolant temperature sensor is below and slightly to the rear of the throttle body. It points toward the drivers fender or may be angled to the rear, but it is in that general location, and is threaded into the intake manifold.
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The item in your photo is the IAC. A set of JIS, Japanese Industrial Standard, screwdrivers work better in those blasted screws. Another option is one of those hammer blow type drivers. The impact and twist, within reason, sometimes will help. Code 041 for the cam sensor may or may not cause rougher than normal idle and low speed depending on how close the injector timing is every time you start it. It shouldn't stall the engine, at least not by itself, but may magnify something else that is also amiss. You can operate with the MAF disconnected but it is only to help narrow the focus if there is a problem. If yours is only misbehaving when cold, it will be more difficult to find if it goes away when warmed slightly.
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Is the check engine light on? Idle air control is on the rear of the throttle body. The actuator faces to the drivers side, two non-magnetic stainless screws hold it in. Remove and clean the inside passageway and pintle on the electric actuator. Those steel pipes, two of them, are for coolant flow to warm the throttle body and prevent icing. Do not disturb them unless you have new gaskets and seal.
If that doesn't help, unplug the MAF and see if the cold start issue gets better. Do you know how to access onboard diagnostics?
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I have done three of these, The sway bar links to the frame should be dropped down. The heat shield for the exhaust forward of the tank needs to at least be loosened because they somewhat overlap the fuel tank. I have never found anything else that needs to removed, aside from the fuel fill hose, vent hose and fuel lines (3). Watch for the thick tar paper isolators that are between the tank and body. They sometimes stick and get displaced.
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Not only are the permanent steel lines a problem but the fuel tank is under the area where a back seat would be. It is forward of the rear axle. The fuel pump itself is in between the little cargo compartments behind the front seats.
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7 hours ago, Barney Eaton said:
Allow me to vent a little on tires........ my Reatta has stock size tire and the sidewall rates them at 1521 lb each at 41 psi.
Do the math and those 4 tires could support a 6084 pound vehicle when inflated to 41 psi.
The information I have says a 1991 convertible weighs 3593 pounds or about 60% of the tire load capacity.
If we assume the load capacity of a tire is directly proportional to the pressure, then what psi could we safely use
on that tire? For this exercise lets say the Reatta weight is 4000 .... (factory weight + 2 - 200 pound passengers + gas)
Using those numbers it comes out that 26.9 psi would safely carry the 4000 pound vehicle. My Reatta door sticker
recommends 30 psi. You can run whatever tire pressure you choose but 28 - 30 is a good range.
I have always stagger inflated my Reatta tires due to the 65%F x 35%R weight distribution in my normal daily driver mode. 34-35 psi front and 30psi rear. 225 tires on 16" wheels
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As a follow up to the knock sensor: Even though it is a pipe thread on the connection to the block, it does not seal any fluids inside the block. The passageway it threads into is a drilling for an oil passage from the oil pump further into the block. There is a pipe plug a couple inches inside the block to seal that passage so no fluids should be present when knock sensor is removed. The torque requirement is only 14 lb/ft or so.
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A low mileage car sounds like a good find👍
Has the ignition coilpack, and ignition module below it, been replaced? If not, look for a sticky ooze leaking out between the two pieces. If this is observed, it is a sure sign it needs to be replaced. Plugs and wires as well of course. If they have been replaced already, double and triple check the rear spark plug cables are on the correct cylinders. This may seem rudimentary, but they happen to get mixed up more often than you might think.
The knock counter should reset to zero every time the ignition is turned on. There is always some start up "noise" so it is normal for the counter to show up to a couple hundred counts after starting but it should not continue to increase during normal driving. If the knock sensor was replaced recently, it will be overly sensitive if it was over tightened.
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14 hours ago, PaulP117 said:
It doesn’t seem like jasper has any 3800’s. And that site I previously linked said they have none in stock and no ETA on it. And I’m running out of places to look when it comes to getting the same 3800. Does anyone know what the difference is between the 91 reattas engine and the 1995 - 1996 Buick lesabre’s engine? Besides the different colors intake and cover. Is there any reason not to think that block should fit my year model 3800, and its parts? Such as the intake and various brackets and bell housing bolts
This is one I found that seems available which is why I ask.
That is a Series 2 engine and parts cannot me mixed and matched with the existing engine. The Series 2 came out in 1995 in the naturally aspirated version. The supercharged variant of the Series 2 arrived in 1996. 3800's through 1994 should work. That said, a complete Series 2 engine could be substituted with some adapting.
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I hope you can find a good replacement engine. The sad fact is the Series 1 engines have been out of production for over 25 years so the salvage yard supply is dwindling although a rebuilder may be good to go. I remember years ago the yard guys said they couldn't give away the older LN3's because they were so reliable🙃 Rebuilding your own engine is getting harder and more expensive, although the expense for non-SBC has always been high. Replacing cam and bearings, no big deal, but once into machine work, the rabbit hole gets deeper fast☹️
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Thanks for letting us know. Your conjecture sounds much like what our dear departed Pagette has said. Good luck and I hope all the associated parts check out👍
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No personal experience but a previous knowledgeable engine expert, Pagette, mentioned what he called dropped cam bearings on more than one occasion which caused lower oil pressure. No mention of breaking the camshaft but ??? Kind of a chicken and egg question
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How many miles at the time of failure? Unusual problem to be sure. The 3800 is a non interference engine so there shouldn't be collateral damage. Thanks for posting the details.
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Nicely done Jon👍
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2 hours ago, minor4326 said:
Funny how some cars use a solid piece and Reatta uses a shock.
I have a Ford Ranger from last century, 4.0 liter V6 which also has a similar shock type setup. It isn't as centered relative to the crankshaft, but it is RWD as well? It has some sort of flex mounted weights on the rear of the transfer case also. My assumption it is all for NVH reduction. Noise, vibration, harshness?
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This is what a complete assembly looks like. A little crusty but at least you can get an idea of the parts.
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It mounts top and bottom like an old style sway bar end link. Rubber cushion and washer on both sides of each end.
I agree with Dave. My boys and I have three cars, one each of 88 through 90, and none of them have that little shock in place, nor the brackets.
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Unfortunately, more than tired and I appreciate the heads up. It is shown sitting on a grass field and if it has been there for an extended time, it is a sure way to have everything underneath begin to rust. Despite the low vin #, it has become a parts car.
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Cold start problem
in Buick Reatta
Posted
If you replaced the magnet for the cam sensor, did the 041 code go away? The TPS idle value looks good, but what does the travel and maximum value look like?
A substantially high TPS at idle can cause an incorrect idle speed but it's primary function is to indicate the throttle position in real time. The MAF sensor tells the ECM what the actual airflow is entering the engine as a result of the throttle opening, sort of a cause and effect.