Weber Tuning Problems
#1
Registered User
Thread Starter
Weber Tuning Problems
So, I finally got my truck running with a new Weber carb. It idles cleaner than ever, but if you give it gas too fast, even before the secondary barrel opens,
it bogs really bad. Then, when the secondary is opened at all, it backfires out the carb.
My carburetor did not come with a tuning guide or anything, so I'm pretty much stuck.
If anyone could help, that'd be great.
it bogs really bad. Then, when the secondary is opened at all, it backfires out the carb.
My carburetor did not come with a tuning guide or anything, so I'm pretty much stuck.
If anyone could help, that'd be great.
#2
Registered User
Before we can knowledgeably help we need some . . . knowledge from you. Starting with . . .
What is the condition (tune, compression, equipment, etc.) of the engine?
What jets does your carb have in it? Which choke? What is the fuel pressure set at?
Pictures are worth 1k words too.
What is the condition (tune, compression, equipment, etc.) of the engine?
What jets does your carb have in it? Which choke? What is the fuel pressure set at?
Pictures are worth 1k words too.
#3
Registered User
Thread Starter
The engine has around 120 psi of compression, for all of the cylinders. With the previous aisin carb, it ran okay, but it would have weird problems such as cutting out after a few minutes of running.
When I installed the weber, I removed the EGR and all vacuum lines except the vacuum advance.
I am not running a regulator, however, I am using a gravity fed tank for testing purposes. I have also tried using the electric fuel pump I am going to use with no different results.
I am not sure what jets, however looking down into the bowl, the two visible jets say 160 and 170.
Here are some pictures
When I installed the weber, I removed the EGR and all vacuum lines except the vacuum advance.
I am not running a regulator, however, I am using a gravity fed tank for testing purposes. I have also tried using the electric fuel pump I am going to use with no different results.
I am not sure what jets, however looking down into the bowl, the two visible jets say 160 and 170.
Here are some pictures
#4
Registered User
I believe the 22R Toyota low compression spec is around 120 and really should be around 170 or so.
Did you do the compression test hot or cold ? Was it with throttle open or closed?
It looks like the stock fuel pump is still there is it working? I also see some disconnected hoses?
It looks like your #2 and 3 plug wires are sitting on a hot part.
Did you do the compression test hot or cold ? Was it with throttle open or closed?
It looks like the stock fuel pump is still there is it working? I also see some disconnected hoses?
It looks like your #2 and 3 plug wires are sitting on a hot part.
#5
Registered User
Thread Starter
I did the compression test cold with the throttle plates closed a while ago with the stock aisin.
The stock fuel pump is broken (I need to get a blockoff plate for it) which is why I have the electric pump.
That disconnected hose is one of the original hoses for the mechanical pump. I believe it was the return line to the fuel tank. I will be plugging it.
The fuel line to the carb is going to a gravity fed tank currently, however I will be installing a fuel pressure regulator today.
Thank you for your input. I will be performing a hot compression test, and moving the spark plug wires.
The stock fuel pump is broken (I need to get a blockoff plate for it) which is why I have the electric pump.
That disconnected hose is one of the original hoses for the mechanical pump. I believe it was the return line to the fuel tank. I will be plugging it.
The fuel line to the carb is going to a gravity fed tank currently, however I will be installing a fuel pressure regulator today.
Thank you for your input. I will be performing a hot compression test, and moving the spark plug wires.
#6
Registered User
Thread Starter
I performed a hot compression test and it was still 120 psi
What do you think the cause is of the low compression, possibly valve issues, or is the engine just conked out?
What do you think the cause is of the low compression, possibly valve issues, or is the engine just conked out?
#7
Registered User
Was it with all the plugs out and open throttle?
Also, were all the cylinders the same?
The next step would be a leak down test to determine if it is valves, rings, etc.
Also, were all the cylinders the same?
The next step would be a leak down test to determine if it is valves, rings, etc.
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#8
Registered User
Thread Starter
Cylinders 1 and 2 are 120 psi cold with throttle open
Cylinders 3 and 4 are 160 psi cold with throttle open
I will likely be performing a leakdown test in the near future.
Cylinders 3 and 4 are 160 psi cold with throttle open
I will likely be performing a leakdown test in the near future.
#9
Registered User
P.S. There are (or have been) several 22R engines on CL over the summer - a good builder motor is one way to go if you need one.
Last edited by L5wolvesf; 09-22-2018 at 02:29 PM.
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