454 TBI, yes/no good/bad idea?

[bkahler]

Nick, pictures are always nice to have. It's amazing what details can be gleaned from looking at pictures of someone else's coach.

Just yesterday I was looking at WayneG's TBI upgrade website and came across this picture of the front of his engine.



I had never seen an adjuster on the alternator like he has. Adjusting the alternator, especially while laying on top of the engine is a real pain. Having an adjuster just makes so much sense. Not sure if that is a factory item or home made but I plan on fabricating one and installing it while my engine is still on the test stand.

So in answer to your question, yes please post pictures!

Brad

[Boom Sounds]

Hi all,

Finally got Cosmo out this weekend and had a very enjoyable few days on Souther England's Jurassic Coast http://jurassiccoast.org/discover/ga...st/lyme-regis/ Highly recommended if you ever travel in the UK.

Anyhow, I also took the opportunity to have a look at the TBI set up. Here are some pictures and part reference numbers. It's all stock kit. There is very little (if any) clearance between the top of the air filter housing and the underneath of the dog house.

454 Big Block Gen V stamped with 10114182
GM ROCHESTER 7.4 454 TBI THROTTLE BODY 17091045
Injection Intake Manifold 10085698

[Boom Sounds]

TBI pictures

[Boom Sounds]

TBI pictures

[Boom Sounds]

All tied into a 454/4L80E with the obd1 diagnostics. Starts like a champ plus good fuel economy on cruise control with the overdrive.


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[bkahler]

Nick, thanks for the pictures! Looking at them in detail has explained a few things about where parts are mounted and most importantly how the cable bundles are routed.

It appears the main harness comes in from the left rear of the block which explains a lot about what I'm seeing with the aftermarket harness that I have purchased.

Thanks again!

Brad

[Boom Sounds]

No worries Brad, just let me know if you need any more info.

As you can see, I need to get a refurb kit for it and replace the gaskets. Do you happen to know the best make? I am assuming AL Delco, but there look to be cheaper aftermarket options. What do you reckon? cheers
Nick

[bkahler]

Originally Posted by Boom Sounds

No worries Brad, just let me know if you need any more info.

As you can see, I need to get a refurb kit for it and replace the gaskets. Do you happen to know the best make? I am assuming AL Delco, but there look to be cheaper aftermarket options. What do you reckon? cheers
Nick

Nick, why do you think the throttle body needs to be refurbished? Are you having any specific problems?

If it's running good I wouldn't mess with it!

If you have access to the PCM could you jot down the numbers and letters on the cover? The PCM should look something like this:



Brad

[Boom Sounds]

Hi Brad - I've got an intermittent problem with power loss. 99% of the time she is rock solid - never had a problem cruising down the Motorway. However, if I have pulled off the freeway and am running at a very slow speed, she can fail to pick up any power; I crawl at 10mph max. It usually clears after 10 mins of trying. I heard those TBI gaskets can fail giving rise to minor vacuum loss so thought I would try there. However, when I had a look last weekend I noticed the pre heater hose had failed and was totally loose, so will fix that first. When the power problem occurs, the check engine light comes on and the OBD1 throws up a 43 knock sensor error. It disappears again when the power picks up, so not a showstopper but annoying and I need to fix it before we head off for vacation to Italy because I have to drive through the French Alps.

Any thoughts on this?

Thanks
Nick



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[Boom Sounds]

I'll have a look for that PCM ref this weekend.




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[bkahler]

Originally Posted by Boom Sounds

Hi Brad - I've got an intermittent problem with power loss. 99% of the time she is rock solid - never had a problem cruising down the Motorway. However, if I have pulled off the freeway and am running at a very slow speed, she can fail to pick up any power; I crawl at 10mph max. It usually clears after 10 mins of trying. I heard those TBI gaskets can fail giving rise to minor vacuum loss so thought I would try there. However, when I had a look last weekend I noticed the pre heater hose had failed and was totally loose, so will fix that first. When the power problem occurs, the check engine light comes on and the OBD1 throws up a 43 knock sensor error. It disappears again when the power picks up, so not a showstopper but annoying and I need to fix it before we head off for vacation to Italy because I have to drive through the French Alps.

Any thoughts on this?

Thanks
Nick

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I just did some googling and found this statement:

A knock sensor code isn't always triggered by a defective knock sensor. It can be triggered by a malfunctioning EGR system, a lean air-to-fuel ratio, worn ignition components, a cooling system problem, or an engine mechanical problem.

My first guess would be the EGR system.

Brad

[Boom Sounds]

Thanks for that. Interestingly, Chris Claw was also having some unusual power issues with his TBI and his was caused by a collapsed EGR hose - I'll check there first.


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[Boom Sounds]

Interesting that it only really happens from a stop or idle, which does indicate it might be related to EGR valve fault.

This from classic winni site;
EGR is considered a `metered intake leak' and was developed to reduce the combustion temperatures to below 2,500 degrees, the threshold where NOx is created. Not unlike putting a brick in your lavatory to lower the volume of water used, the EGR valve meters a readily available inert gas (actually exhaust gas which contains a lot of very inert Carbon Dioxide) into the combustion chamber to effectively reduce the volume. Smaller effective displacement means less fire, and less heat and thus lower temperatures, thereby controlling NOx emissions.

During full acceleration, the EGR valve is disabled to facilitate combustion and fill the combustion chambers, a set of conditions called wide open throttle (WOT). Were the EGR valve to be invoked during full acceleration, it would inhibit the acceleration by reducing the capacity of the fuel combustion chambers. At the other end of the scale, when the car is idling it is especially sensitive to the composition of air and fuel in the combustion chamber and therefore the EGR valve is turned off. Should the EGR valve still be in operation when the car is idle, the vehicle is likely to stall or stumble.

Typically the EGR system is made up of several components that control the operation over several situations so it isn't necessarily the EGR valve itself tha is the problem.



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[bkahler]

That seems to match your symptoms pretty well.

Looks like you have a starting point to look for the problem.

Good luck!

[bkahler]

Thought I would post a picture of the surge tank that I will be using for my TBI installation. It's a 1/2 gallon tank with AN fittings on it.



The bottom fitting goes to the high pressure pump, the right most fitting is the feed from the low pressure pump, the top fitting is the surge tank return to the main tank and the top left fitting is the return from the Throttle Body.

I'm going to use external pumps as I have no desire to install an in-tank pump. I realize that might be the best approach but lots of research seems to indicate that surge tanks are a very viable alternative to in-tank pumps.

[PeterH-350LE]

Originally Posted by bkahler

Thought I would post a picture of the surge tank that I will be using for my TBI installation. It's a 1/2 gallon tank with AN fittings on it.

Attachment 261567

The bottom fitting goes to the high pressure pump, the right most fitting is the feed from the low pressure pump, the top fitting is the surge tank return to the main tank and the top left fitting is the return from the Throttle Body.

I'm going to use external pumps as I have no desire to install an in-tank pump. I realize that might be the best approach but lots of research seems to indicate that surge tanks are a very viable alternative to in-tank pumps.

so, do you have 3/8" all the way from the main tank via surge tank on to the throttle body and 1/4" for the return lines? I think that is the recommended size? The previous owner of my 310 replaced all the hard lines with 3/8 as well for that reason.

[bkahler]

Originally Posted by PeterH-Airstreamer

so, do you have 3/8" all the way from the main tank via surge tank on to the throttle body and 1/4" for the return lines? I think that is the recommended size? The previous owner of my 310 replaced all the hard lines with 3/8 as well for that reason.

3/8" suction from main tank to LP pump and 3/8" from the LP pump to the surge tank, 5/16" from the surge tank to the HP pump, 3/8" from the HP pump to the Throttle Body, 5/16" from the Throttle Body return to the surge tank and 5/16" from the surge tank to the main tank.

This combination has been used successfully in similar applications. The LP pump flows over 55 GPH which is more than sufficient for the 454. None of the lines are very long with the longest probably being around 5' or 6' from the HP pump to the Throttle Body Body and its matching return line to the surge tank.

All of these components will be mounted on the frame rail by the main tank.

[Boom Sounds]

good TBI info here.

http://www.thirdgen.org/forums/tbi/2...check-out.html

[bkahler]

I've found the people on Gearhead-efi are very helpful. Lots of good information.

[bkahler]

I reached a very minor mile stone today. I set up a TBI test bed on my dining room table to verify all of the TBI components were working and to verify the data logging capability.


I was able to collect data from the sensors, the injectors fired and I had spark at the spark plugs

Next step is to install the throttle body using the adapter plate that I made and move all of the components to the engine itself. I'll then do another test run of the engine logging the data at the same time. Once done I'll send the data to the guy doing the tuning. While he's tweaking the parameters I'll start installing the engine in the chassis!

Brad