Technical Throttle problem in cornering

[Havemann]

Hi There.
I'm new on this message board, but would like if you guys could give me some info on my problem. I have bought my exxy in Aug last year. Love the car, and actually was the first car I drove when I was 13... Well, my problem is as follows : I have switched my 1300 motor to a 1500 which I got from a Fiat Ritmo 85, and have rebuilt the whole engine, and goes a good 200kh/h - with a good acceleration, but as soon as I get to a corner, the throttle doesn't work as it should. The whole car hesitates, and struggles if I flat it out in a corner. Well, don't know if I have explained the situation well enough, but the car feels as if it does not get enough fuel as soon as I corner at a steady 80km/h. I thought that it might be the fuel that floods the carb as soon as I fully excelerate in a turn, but it has no problems pulling away in a straight line... I hope someone could help me.

 

[sumplug]

Hi There.
I'm new on this message board, but would like if you guys could give me some info on my problem. I have bought my exxy in Aug last year. Love the car, and actually was the first car I drove when I was 13... Well, my problem is as follows : I have switched my 1300 motor to a 1500 which I got from a Fiat Ritmo 85, and have rebuilt the whole engine, and goes a good 200kh/h - with a good acceleration, but as soon as I get to a corner, the throttle doesn't work as it should. The whole car hesitates, and struggles if I flat it out in a corner. Well, don't know if I have explained the situation well enough, but the car feels as if it does not get enough fuel as soon as I corner at a steady 80km/h. I thought that it might be the fuel that floods the carb as soon as I fully excelerate in a turn, but it has no problems pulling away in a straight line... I hope someone could help me.

Think you will find the X1/9 engine sits at a different angle to the Ritmo, and i bet the carb is at an angle and so as soon as you hit a corner, the float chamber empties or floods, giving you driving problems. Solution, is to use the X1/9 1500 carb and manifold. I would also look at the oil pickup in the sump as it might be having oil issues due to angle.

Andy.

 

[Havemann]

Well I had the same problem with the 1300 org. motor, and have mounted the x1/9 sump, and oil pump. If it was the angle of the motor, the car would accelerate badly, but is only in cornering. The motor is futhermore the same as the 1300 x1/9 motor, and the motor number match the motor number of a 1500 x1/9...

 

[jimbro1000]

Did you use an X1/9 inlet manifold or the ritmo one? Again the angle is wrong and it would effect the float chamber levels - the floats are hinged sideways so would remain stable under straight line acceleration.

The fact that you are getting a repeatable problem from before suggests that the angles are aren't at fault. I would suggest taking a very good look at the carburettor, float levels and the quantity of debris in the carburettor itself.

The only other place I can think to look is the fuel tank and the ignition system (in case the bob weight mechanism is at fault).

 

[Havemann]

As far as I remember I used the 1300 intake manifold. But will check this. What do you mean by the bob weight mechanism? I used the 1300 ign. system... And I have tried with a elctrical fuel pump as well. The carb. is from the 1500 motor, and had the same problem with the 1300 carb, but the manifold might be the problem then, or the "bob weight mechanism".

 

[jimbro1000]

The bob weight mechanism is the ignition advance inside the distributor. I don't think it would be the source as it is spinning continuously but it is one of the parts in the system that might cause this (normally either it works or it doesn't).

The ignition leads should be checked to make sure they can't move and short out.

That would rule the ignition side out (an unlikely culprit but it needs eliminating).

Rewinding a bit - when did this problem first start? Has it always been there?

If you did use the 1500 carb did you convert it to manual choke or was the water feed for the autochoke already there? If so then you didn't start with the 1300 manifold.

If you are still using the original carburettor then your problem is almost 100% definitely going to be the float level. It isn't hard to check and fix but technically it requires a new gasket. You can do it with the carb on the car if you are careful but it isn't easy. It is far easier to remove the carb to do the job.

 

[sumplug]

Could also be the fuel tank sender unit thats faulty or in need of adjustment. the fact it only does it round a corner points definately to fuel starvation. Iam wondering if you have a faulty needle valve? Had a similar problem on a 128 many years ago.

Andy.

 

[Havemann]

Well the problem has always been there, ever since I got the car. I swopped the engine to a 1500, due to clattering sounds with the 1300 - I think it was a main bearing. I then changed all the parts which I could see was worn, and cleaned the whole motor out for rust, and grime. I then installed the 1500 carb, but the car did not run very well. I changed back to the 1300 carb which I also had the same problem with, and then cleaned the 1500 carb out, but did not mount new gaskets in the carb. When I mounted the 1500 carb again it ran much better, but still had the problem in cornering. So I don't know what the problem can be - can it be that both carbs is worn? The fuel tank I have not done anything with, but doesn't fuel reach the carb whatever the fuel tank sensor does? I have also had a electric fuel fump on the car, but it did not make any difference, exept for a lot of humming in the car, so I mounted the old mechanical pump again. Is it a good idea to invest in a carb gasket set, or should i bee on the look out for a new carb? I heard that a Ford XR carb should fit, and shoud give a little more BHP, but I don't know if I rather should try get hold of a Weber 40 DCOE manifold, and mount my two twin DCOE's? How many HP will I gain by doing this, and would my corner fuel stability become better?

 

[jimbro1000]

The carb you have for the 1500 can be jetted to give you whatever state of tune you desire within reason. The limiting factor is air flow and air volume.

Without changing the camshaft, exhaust and air filter you are not going to really step outside what the standard DATR (DMTR from the 1300) can offer provided you have the right carburettor to start with. The one from the Ritmo is not the same as the once from the X1/9 and comes with different sized venturi.

If the problem you are talking about is consistent between both engines in your experience of the car then you can be sure it is something that hasn't been changed during the transplant. It is possible that both carburettors have the same fault but highly unlikely.

One of the things I haven't previously considered is an air leak into the carburettor (although one could argue that an incorrect float level amounts to much the same thing). Try running the car with the air filter housing removed and see if it makes a difference. I doubt if it is the housing itself but it provides enough mass to create leverage on the carburettor and manifold when cornering.

Getting back to the other parts - the fuel system in general I'm guessing hasn't been changed so you still have the same pickup in the fuel tank. I don't recommend taking the tank off as it is usually a surefire way of creating a hole when the straps are removed but taking the pickup and sender out of the tank for a clean should be quite feasible.

If you haven't already done so the flexible fuel pipes are likely to be perished so it may be worth replacing them.

Check the entire electrical system, from earth straps to the ignition feed and make sure nothing can flop around. Most of the wiring is fairly well restrained but not all of it.

The carburettor itself is always worth cleaning and setting up properly. You can't do the job properly without the main gasket and if you really want to do it right then you need a new needle valve assembly too (they generally come as seperate kits) and between the two kits you should also have all the seals for the adjustment screws (and maybe the screws as well). The problem is at the end of the job you will likely need some help getting the carb set up properly.

 

[Havemann]

Well cheked all things now, and readjusted the float level, found the numbers in the X1/9 Haynes book, but have an even bigger problem now, the car misfires as soon as I get around 5000RPM... And all this happened right after I adjusted the thw float level, so I tried with the original settings again, and still the same problem, now the car does not hesitate in corners, but all the time (above 5000rpm) Please let me know what I am to do? I have thought about the timing? can this be the problem now? I just don't understand how this could cause the car to react the way it does. I have tighned the screwes again which holds the carb to the manifold, and I know that there was a problem with the carb letting in false air, but can this e the source to the misfireing? Please let me know, because the more problems this gives me, the angrier I get at the car, and harder I press the pedal... Allthough I know this doesn't help...

 

[jimbro1000]

Ok - sounds like we've fixed the initial problem, which is good but it sounds very much like you have an air leak.

Does the car misfire when stationary and out of gear? Or does it have to be under load? If you can get it to misfire while you work in the engine bay you can use something like WD40 to trace the leak. By working around the carb and spraying it you should find that the spray will briefly seal the leak.

It does sound as if it is an air leak - I used to get the problem on my old XR2 and it drove me absolutely nuts!

 

[sumplug]

I agree with JB. It sounds like the mixture is going lean at high revs due to a leak. Check around the carb base and inlet manifold to head. Also check your second choke is working ok. On the otherhand, a missfire can be caused by over fueling too, so whip a couple of plugs out to check the misture. black soot is over fuel, and whitish under fuel.
Another problem could be the coil breaking down at high revs or plug leads or even the wrong plugs being used. Again its all to check out. One way to check the plugs are firing, is to swap the plugs around, and if the missfire plug moves, then suspect plugs. Try some other plug leads if you have some spare.

Andy.

 

[Havemann]

Hi There.

I want to start by saying thanks a lot for all the help and info!!!

Well today I went out and bought a used needle valve, and seat for my carb, and switched this as well as the top of the carb. But I read in the x1/9 haynes manual that the float must be adjusted at certain mesurements, but i cannot beleive the figures that they have in the book, becase the last three carbs I have taken apart the float measurements are round about 35mm from gasket to fully open #1 (bottom of the float "float face", furthes end out) and closed round about 1-3mm #2. In the X1/9 book it sais that the float should have a traveling distance of 9mm and the lower measurement #2 must be 6mm, and upper 15mm #1 for the 1300, and for the 1500 the lower measurement must be 6.75-7.25mm #2. So I tried to adjust the the float to these measurements, but all of a sudden the car didn't want to pull at all (hesitating), so I returned it to the settings which it was to start with. #1 = 40mm, #2 = 1.5mm, so now I can drive the car.

Then I tried to adjust the timing, and turning the housing clockwards, I got rid of the high speed rpm problem, but then the timing makes a noise if I load the car (4. gear at about 40km/h) or pedal to the metal (timing knock). So I went for a drive tonight after dark, and saw that there was a lot of small sparks coming from the ign. leads, espesially from the HT lead coming from the coil. So tried to clean them off with some meths, but still they make sparks, so I better invest in new leads, and plugs.

The last thing I have done, and I am worried about is the jets. I have taken the whole carb off, and fittet new gaskets under the carb, facing the manifold. But then I thought that I could just as well check the jets, (main, ideling, and the emulsion tubes, but got confused by which sizes they must be... Taking from the left to the right (so I get this staight and confirmed) I'll call the one at the utmost left #1, standing behind the car, with the ideling speed screw facing you. #1 is the primary ideling jet, #2, the primary main jet, # Secondary Main jet, and #4, Secondary ideling jet. Is this correct? And could you tell me exactly what their function is, and most important what sizes they must be?

I have a mechanic friend who has had the car coupled to a testing station, but I'm not sure he knows to well what he was doing, because he said that the primary jet must be much larger, and used a small drill to make the hole larger... And even if this goes against all my beleif, the car drove there after, and went a little better, but this isn't my way of doing things.. So I went out and found some different jets, and tried a few, but at last I fitted the ones I had before. (wondering if the car got enough fuel, not burning the valves) The car always drove fine, but I'm wondering if I'm not missing out on some Hp's due to his tampering, and if this couldn't be the reason for my problems. In the end he couldn't get the car to be within the limitations/factors of the tesing machine in any case..

Thanks a million for you help. Hope soon to get my car in top driving shape again.

Marcel.