Eddie Trickett Posted October 26, 2020 Report Share Posted October 26, 2020 Just replaced metering unit and distributor setting timing on both. Car starts up straight away but accelerator does nothing and car is hissing and spitting. Accelerator moves linkages but doesn't have any effect on engine. With strobe on timing marks the timing is not steady. Any suggestions? Thanks Eddie Quote Link to post Share on other sites
michaelfinnis Posted October 26, 2020 Report Share Posted October 26, 2020 Accelerator moves throttle butterflies, but MU fuelling is controlled by vacuum. Problem with the vacuum chamber on the MU or the hose to it? Mike. Quote Link to post Share on other sites
Eddie Trickett Posted October 26, 2020 Author Report Share Posted October 26, 2020 Mike, That might have been part of the problem. I pushed the hose further in the mu before last start. But engine is still spitting and timing is eratic. Getting closer to running OK but not there yet. Quote Link to post Share on other sites
Mike C Posted October 26, 2020 Report Share Posted October 26, 2020 I assume you don't have a carb distributor with a vacuum line connected. I'd connect a vacuum gauge to the brake booster connection and check the vacuum is stable and falls when you open the throttle- no burn't valves etc. If the vacuum's stable and the timing's right you have a distributor problem Quote Link to post Share on other sites
JohnC Posted October 26, 2020 Report Share Posted October 26, 2020 Sounds like you may have a combination problems. As you just replaced the MU and distributor, the most likely cause is in one or both of those, or in the stuff you disturbed in the process. Where did you source the replacements from? The erratic timing can only be either a worn distributor or, at a stretch, tired harmonic balancer rubber. Most likely distributor. Shouldn't cause the lack of response though. I'd call the supplier and get their opinion. Was it fully reconditioned? I had mine done by Martin Jay and the timing is rock-solid. The lack of response could be any number of things. I'd start by re-timing the distributor. At the risk of teaching you to suck eggs, are you certain you have the firing order correct, and that #1 is firing at the correct time in its stroke (i.e., you're not out by 1 cylinder)? Then I'd do a tongue test on the MU hose to check the vacuum chamber & hose aren't leaking. Follow that by ensuring the fuel enrichment lever on the MU is returning fully to the closed position. Next on my list would be to look for ignition faults. Start up in a dark garage (yes, leave the door open, it's not that bad!) and look for tracking. Swap the plugs, points and rotor arm. Leads less likely a problem, assuming they're properly seated. After that, it's time to re-balance butterflies and check the valve clearances. And have a drink. Please report back. This forum is a great source of knowledge, much based on frustrating experiences! JC Quote Link to post Share on other sites
michaelfinnis Posted October 27, 2020 Report Share Posted October 27, 2020 Hi, two thoughts; What about refitting the original distributor, not too much work and that might prove if the new one is the problem or not. Secondly, what RPM is the car idling at, and is it stable? Mechanical ignition advance comes in around 900 RPM, so could the movement of the timing marks be due to erratic engine speed rather than a problem with the distributor? Mike. Quote Link to post Share on other sites
Eddie Trickett Posted October 27, 2020 Author Report Share Posted October 27, 2020 Many thanks everyone for the advice. Car now seems to be running reasonably well,starting straight away, ticking over at 800-900 rpm and revving up OK. Timing still slightly erratic but maybe it is the distributor kicking in. Not sure what has made things better. Looked at the Triumph book rather than the Haynes manual and misread the ignition timing instructions and set at 24BTDC. Engine ran smoothly at that, then I realized the mistake and set back to 12BTDC and it still runs OK. Need to take it out for a run to see how it performs on the road. For info the distributor is original, just back from Martin Jay, metering unit and injectors reconditioned by Neil Ferguson and bosch fuel pump, filters and relief valve from Malcolm in Wrexham so there shouldn't be any reason why it won't run OK if I have set up the timing properly. Eddie Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.